Simplifying expressions with rational exponents and radicals answer key

Video transcript

- [Voiceover] So I have an interesting equation here. It says V to the negative six fifths power times the fifth root of V is equal to V to the K power, for V being greater than/equal to zero. And what I wanna do is try to figure out what K needs to be. So what is... what is K going to be equal to? So pause the video and see if you can figure out K, and I'll give you a hint, you just have to leverage some of your exponent properties. Alright, let's work this out together. So the first thing I'd want to do is being a little bit consistent in how I write my exponents. So here I've written it as negative six fifths power, and here I've written it as a fifth root, but we know that the fifth root of something... we know that the fifth root... the fifth root of V, that's the same way, that's the same thing as saying V to the one fifth power, and the reason I want to say that is because then I'm multiplying two different powers of the same base, two different powers of V. And so we can use our exponent properties there. So, this is gonna be the same thing as V to the negative six fifths times, instead of saying the fifth root of V I can say times V to the one fifth power is going to be equal to V to the K. It's gonna be equal to V to the K power. Now, if I'm multiplying V to some power times V to some other power, we know what the exponent properties would tell us, and I could remind us. I'll do it over here. If I have X to the A times X to the B, that's going to be X to the A plus B power. So here, I have the same base, V. So this is going to be V to the, and I could just add the exponents. V to the negative six fifths power plus one fifth power, or V to the negative six fifths plus one fifth power is going to be equal to V to the K. Is equal to V to the K. I think you might see where this is all going now. So this is going to be equal to V. So negative six fifths plus one fifth is going to be negative five fifths or negative one. So all of this is going to be equal to negative one, and that's going to be equal to V to the K. So K must be equal to negative one, and we're done. K is equal to negative one.

Video transcript

- [Instructor] Which of the following values is equal to the value above? And we've got this expression here with a bunch of negative fractional exponents. And at first, you might say okay, how do I deal with this? I don't know that the fifth root of three is, much less the negative fifth root, and this one third to the negative two fifths. How do I simplify this? And the key realization here, is that one third is the same thing as three to the negative one power. One third is the same thing as three to the negative one power. And if we do that, I suspect that we're gonna be able to get similar bases here. Let me rewrite the whole thing. So, it's gonna be three to the negative one fifth times, instead of writing one third, I can write three to the negative one power, to the negative two fifths power. And now we can just use up our straight exponent rules to simplify things a little bit. So this business right over here, that I'm squaring in this orange color, if I raise something to an exponent, and then raise it again to another exponent, that's going to be the same thing as taking our original raise and raising it to the negative one times the negative one times negative two fifths power. So if I raise it to the negative one, and then the negative two fifths, that's the same thing as raising three to the negative one times negative two fifths power. And so this over here is sill going to be three to the negative one fifth. And so this is going to be equal to three to the negative one fifth times, now negative one times negative two fifths, that's going to be positive two fifths. So we times three to the two fifths. And now we have a situation where we have the same base. We have the product of three to the negative one fifth times three to the positive two fifths. This is going to be equal to, we can take our base three, is gonna be three to the negative one fifth plus two fifths power, plus two fifths power. If you have the same base, the product of that base raised to one exponent and that same base raised to another exponent, that's the same thing as that base raised to the sum of those exponents, a classic exponent property. I encourage you to go on Khan Academy if this is looking foreign or if you need some review. But now this is pretty straightforward. This is going to be equal to, this is is going to be equal to three to the negative one fifth plus two fifths is just one fifth. And there you have it: three to the one fifth power.

  1. Last updated
  2. Save as PDF
  • Page ID46427
  • Learning Objectives

    By the end of this section, you will be able to:

    • Simplify expressions with \(a^{\frac{1}{n}}\)
    • Simplify expressions with \(a^{\frac{m}{n}}\)
    • Use the properties of exponents to simplify expressions with rational exponents

    Before you get started, take this readiness quiz.

    1. Add: \(\frac{7}{15}+\frac{5}{12}\).
      If you missed this problem, review Example 1.28.
    2. Simplify: \((4x^{2}y^{5})^{3}\).
      If you missed this problem, review Example 5.18.
    3. Simplify: \(5^{−3}\).
      If you missed this problem, review Example 5.14.

    Simplify Expressions with \(a^{\frac{1}{n}}\)

    Rational exponents are another way of writing expressions with radicals. When we use rational exponents, we can apply the properties of exponents to simplify expressions.

    The Power Property for Exponents says that \(\left(a^{m}\right)^{n}=a^{m \cdot n}\) when \(m\) and \(n\) are whole numbers. Let’s assume we are now not limited to whole numbers.

    Suppose we want to find a number \(p\) such that \(\left(8^{p}\right)^{3}=8\). We will use the Power Property of Exponents to find the value of \(p\).

    \(\left(8^{p}\right)^{3}=8\)

    Multiple the exponents on the left.

    \(8^{3p}=8\)

    Write the exponent \(1\) on the right.

    \(8^{3p}=8^{1}\)

    Since the bases are the same, the exponents must be equal.

    \(3p=1\)

    Solve for \(p\).

    \(p=\frac{1}{3}\)

    So \(\left(8^{\frac{1}{3}}\right)^{3}=8\). But we know also \((\sqrt[3]{8})^{3}=8\). Then it must be that \(8^{\frac{1}{3}}=\sqrt[3]{8}\).

    This same logic can be used for any positive integer exponent \(n\) to show that \(a^{\frac{1}{n}}=\sqrt[n]{a}\).

    Definition \(\PageIndex{1}\): Rational Exponent \(a^{\frac{1}{n}}\)

    If \(\sqrt[n]{a}\) is a real number and \(n \geq 2\), then

    \(a^{\frac{1}{n}}=\sqrt[n]{a}\)

    The denominator of the rational exponent is the index of the radical.

    There will be times when working with expressions will be easier if you use rational exponents and times when it will be easier if you use radicals. In the first few examples, you'll practice converting expressions between these two notations.

    Example \(\PageIndex{1}\)

    Write as a radical expression:

    1. \(x^{\frac{1}{2}}\)
    2. \(y^{\frac{1}{3}}\)
    3. \(z^{\frac{1}{4}}\)

    Solution:

    We want to write each expression in the form \(\sqrt[n]{a}\).

    a.

    \(x^{\frac{1}{2}}\)

    The denominator of the rational exponent is \(2\), so the index of the radical is \(2\). We do not show the index when it is \(2\).

    \(\sqrt{x}\)

    b.

    \(y^{\frac{1}{3}}\)

    The denominator of the exponent is \(3\), so the index is \(3\).

    \(\sqrt[3]{y}\)

    c.

    \(z^{\frac{1}{4}}\)

    The denominator of the exponent is \\(4\), so the index is \(4\).

    \(\sqrt[4]{z}\)

    Exercise \(\PageIndex{1}\)

    Write as a radical expression:

    1. \(t^{\frac{1}{2}}\)
    2. \(m^{\frac{1}{3}}\)
    3. \(r^{\frac{1}{4}}\)
    Answer
    1. \(\sqrt{t}\)
    2. \(\sqrt[3]{m}\)
    3. \(\sqrt[4]{r}\)

    Exercise \(\PageIndex{2}\)

    Write as a radical expression:

    1. \(b^{\frac{1}{6}}\)
    2. \(z^{\frac{1}{5}}\)
    3. \(p^{\frac{1}{4}}\)
    Answer
    1. \(\sqrt[6]{b}\)
    2. \(\sqrt[5]{z}\)
    3. \(\sqrt[4]{p}\)

    In the next example, we will write each radical using a rational exponent. It is important to use parentheses around the entire expression in the radicand since the entire expression is raised to the rational power.

    Example \(\PageIndex{2}\)

    Write with a rational exponent:

    1. \(\sqrt{5y}\)
    2. \(\sqrt[3]{4 x}\)
    3. \(3 \sqrt[4]{5 z}\)

    Solution:

    We want to write each radical in the form \(a^{\frac{1}{n}}\)

    a.

    \(\sqrt{5y}\)

    No index is shown, so it is \(2\).

    The denominator of the exponent will be \(2\).

    Put parentheses around the entire expression \(5y\).

    \((5 y)^{\frac{1}{2}}\)

    b.

    \(\sqrt[3]{4 x}\)

    The index is \(3\), so the denominator of the exponent is \(3\). Include parentheses \((4x)\).

    \((4 x)^{\frac{1}{3}}\)

    c.

    \(3 \sqrt[4]{5 z}\)

    The index is \(4\), so the denominator of the exponent is \(4\). Put parentheses only around the \(5z\) since 3 is not under the radical sign.

    \(3(5 z)^{\frac{1}{4}}\)

    Exercise \(\PageIndex{3}\)

    Write with a rational exponent:

    1. \(\sqrt{10m}\)
    2. \(\sqrt[5]{3 n}\)
    3. \(3 \sqrt[4]{6 y}\)
    Answer
    1. \((10 m)^{\frac{1}{2}}\)
    2. \((3 n)^{\frac{1}{5}}\)
    3. \(3(6 y)^{\frac{1}{4}}\)

    Exercise \(\PageIndex{4}\)

    Write with a rational exponent:

    1. \(\sqrt[7]{3 k}\)
    2. \(\sqrt[4]{5 j}\)
    3. \(8 \sqrt[3]{2 a}\)
    Answer
    1. \((3 k)^{\frac{1}{7}}\)
    2. \((5 j)^{\frac{1}{4}}\)
    3. \(8(2 a)^{\frac{1}{3}}\)

    In the next example, you may find it easier to simplify the expressions if you rewrite them as radicals first.

    Example \(\PageIndex{3}\)

    Simplify:

    1. \(25^{\frac{1}{2}}\)
    2. \(64^{\frac{1}{3}}\)
    3. \(256^{\frac{1}{4}}\)

    Solution:

    a.

    \(25^{\frac{1}{2}}\)

    Rewrite as a square root.

    \(\sqrt{25}\)

    Simplify.

    \(5\)

    b.

    \(64^{\frac{1}{3}}\)

    Rewrite as a cube root.

    \(\sqrt[3]{64}\)

    Recognize \(64\) is a perfect cube.

    \(\sqrt[3]{4^{3}}\)

    Simplify.

    \(4\)

    c.

    \(256^{\frac{1}{4}}\)

    Rewrite as a fourth root.

    \(\sqrt[4]{256}\)

    Recognize \(256\) is a perfect fourth power.

    \(\sqrt[4]{4^{4}}\)

    Simplify.

    \(4\)

    Exercise \(\PageIndex{5}\)

    Simplify:

    1. \(36^{\frac{1}{2}}\)
    2. \(8^{\frac{1}{3}}\)
    3. \(16^{\frac{1}{4}}\)
    Answer
    1. \(6\)
    2. \(2\)
    3. \(2\)

    Exercise \(\PageIndex{6}\)

    Simplify:

    1. \(100^{\frac{1}{2}}\)
    2. \(27^{\frac{1}{3}}\)
    3. \(81^{\frac{1}{4}}\)
    Answer
    1. \(10\)
    2. \(3\)
    3. \(3\)

    Be careful of the placement of the negative signs in the next example. We will need to use the property \(a^{-n}=\frac{1}{a^{n}}\) in one case.

    Example \(\PageIndex{4}\)

    Simplify:

    1. \((-16)^{\frac{1}{4}}\)
    2. \(-16^{\frac{1}{4}}\)
    3. \((16)^{-\frac{1}{4}}\)

    Solution:

    a.

    \((-16)^{\frac{1}{4}}\)

    Rewrite as a fourth root.

    \(\sqrt[4]{-16}\)

    \(\sqrt[4]{(-2)^{4}}\)

    Simplify.

    No real solution

    b.

    \(-16^{\frac{1}{4}}\)

    The exponent only applies to the \(16\). Rewrite as a fourth root.

    \(-\sqrt[4]{16}\)

    Rewrite \(16\) as \(2^{4}\)

    \(-\sqrt[4]{2^{4}}\)

    Simplify.

    \(-2\)

    c.

    \((16)^{-\frac{1}{4}}\)

    Rewrite using the property \(a^{-n}=\frac{1}{a^{n}}\).

    \(\frac{1}{(16)^{\frac{1}{4}}}\)

    Rewrite as a fourth root.

    \(\frac{1}{\sqrt[4]{16}}\)

    Rewrite \(16\) as \(2^{4}\).

    \(\frac{1}{\sqrt[4]{2^{4}}}\)

    Simplify.

    \(\frac{1}{2}\)

    Exercise \(\PageIndex{7}\)

    Simplify:

    1. \((-64)^{-\frac{1}{2}}\)
    2. \(-64^{\frac{1}{2}}\)
    3. \((64)^{-\frac{1}{2}}\)
    Answer
    1. No real solution
    2. \(-8\)
    3. \(\frac{1}{8}\)

    Exercise \(\PageIndex{8}\)

    Simplify:

    1. \((-256)^{\frac{1}{4}}\)
    2. \(-256^{\frac{1}{4}}\)
    3. \((256)^{-\frac{1}{4}}\)
    Answer
    1. No real solution
    2. \(-4\)
    3. \(\frac{1}{4}\)

    Simplify Expressions with \(a^{\frac{m}{n}}\)

    We can look at \(a^{\frac{m}{n}}\) in two ways. Remember the Power Property tells us to multiply the exponents and so \(\left(a^{\frac{1}{n}}\right)^{m}\) and \(\left(a^{m}\right)^{\frac{1}{n}}\) both equal \(a^{\frac{m}{n}}\). If we write these expressions in radical form, we get

    \(a^{\frac{m}{n}}=\left(a^{\frac{1}{n}}\right)^{m}=(\sqrt[n]{a})^{m} \quad \text { and } \quad a^{\frac{m}{n}}=\left(a^{m}\right)^{^{\frac{1}{n}}}=\sqrt[n]{a^{m}}\)

    This leads us to the following defintion.

    Definition \(\PageIndex{2}\): Rational Exponent \(a^{\frac{m}{n}}\)

    For any positive integers \(m\) and \(n\),

    \(a^{\frac{m}{n}}=(\sqrt[n]{a})^{m} \quad \text { and } \quad a^{\frac{m}{n}}=\sqrt[n]{a^{m}}\)

    Which form do we use to simplify an expression? We usually take the root first—that way we keep the numbers in the radicand smaller, before raising it to the power indicated.

    Example \(\PageIndex{5}\)

    Write with a rational exponent:

    1. \(\sqrt{y^{3}}\)
    2. \((\sqrt[3]{2 x})^{4}\)
    3. \(\sqrt{\left(\frac{3 a}{4 b}\right)^{3}}\)

    Solution:

    We want to use \(a^{\frac{m}{n}}=\sqrt[n]{a^{m}}\) to write each radical in the form \(a^{\frac{m}{n}}\)

    a.

    Simplifying expressions with rational exponents and radicals answer key
    Figure 8.3.1

    b.

    Simplifying expressions with rational exponents and radicals answer key
    Figure 8.3.2

    c.

    Simplifying expressions with rational exponents and radicals answer key
    Figure 8.3.3

    Exercise \(\PageIndex{9}\)

    Write with a rational exponent:

    1. \(\sqrt{x^{5}}\)
    2. \((\sqrt[4]{3 y})^{3}\)
    3. \(\sqrt{\left(\frac{2 m}{3 n}\right)^{5}}\)
    Answer
    1. \(x^{\frac{5}{2}}\)
    2. \((3 y)^{\frac{3}{4}}\)
    3. \(\left(\frac{2 m}{3 n}\right)^{\frac{5}{2}}\)

    Exercise \(\PageIndex{10}\)

    Write with a rational exponent:

    1. \(\sqrt[5]{a^{2}}\)
    2. \((\sqrt[3]{5 a b})^{5}\)
    3. \(\sqrt{\left(\frac{7 x y}{z}\right)^{3}}\)
    Answer
    1. \(a^{\frac{2}{5}}\)
    2. \((5 a b)^{\frac{5}{3}}\)
    3. \(\left(\frac{7 x y}{z}\right)^{\frac{3}{2}}\)

    Remember that \(a^{-n}=\frac{1}{a^{n}}\). The negative sign in the exponent does not change the sign of the expression.

    Example \(\PageIndex{6}\)

    Simplify:

    1. \(125^{\frac{2}{3}}\)
    2. \(16^{-\frac{3}{2}}\)
    3. \(32^{-\frac{2}{5}}\)

    Solution:

    We will rewrite the expression as a radical first using the defintion, \(a^{\frac{m}{n}}=(\sqrt[n]{a})^{m}\). This form lets us take the root first and so we keep the numbers in the radicand smaller than if we used the other form.

    a.

    \(125^{\frac{2}{3}}\)

    The power of the radical is the numerator of the exponent, \(2\). The index of the radical is the denominator of the exponent, \(3\).

    \((\sqrt[3]{125})^{2}\)

    Simplify.

    \((5)^{2}\)

    \(25\)

    b. We will rewrite each expression first using \(a^{-n}=\frac{1}{a^{n}}\) and then change to radical form.

    \(16^{-\frac{3}{2}}\)

    Rewrite using \(a^{-n}=\frac{1}{a^{n}}\)

    \(\frac{1}{16^{\frac{3}{2}}}\)

    Change to radical form. The power of the radical is the numerator of the exponent, \(3\). The index is the denominator of the exponent, \(2\).

    \(\frac{1}{(\sqrt{16})^{3}}\)

    Simplify.

    \(\frac{1}{4^{3}}\)

    \(\frac{1}{64}\)

    c.

    \(32^{-\frac{2}{5}}\)

    Rewrite using \(a^{-n}=\frac{1}{a^{n}}\)

    \(\frac{1}{32^{\frac{2}{5}}}\)

    Change to radical form.

    \(\frac{1}{(\sqrt[5]{32})^{2}}\)

    Rewrite the radicand as a power.

    \(\frac{1}{\left(\sqrt[5]{2^{5}}\right)^{2}}\)

    Simplify.

    \(\frac{1}{2^{2}}\)

    \(\frac{1}{4}\)

    Exercise \(\PageIndex{11}\)

    Simplify:

    1. \(27^{\frac{2}{3}}\)
    2. \(81^{-\frac{3}{2}}\)
    3. \(16^{-\frac{3}{4}}\)
    Answer
    1. \(9\)
    2. \(\frac{1}{729}\)
    3. \(\frac{1}{8}\)

    Exercise \(\PageIndex{12}\)

    Simplify:

    1. \(4^{\frac{3}{2}}\)
    2. \(27^{-\frac{2}{3}}\)
    3. \(625^{-\frac{3}{4}}\)
    Answer
    1. \(8\)
    2. \(\frac{1}{9}\)
    3. \(\frac{1}{125}\)

    Example \(\PageIndex{7}\)

    Simplify:

    1. \(-25^{\frac{3}{2}}\)
    2. \(-25^{-\frac{3}{2}}\)
    3. \((-25)^{\frac{3}{2}}\)

    Solution:

    a.

    \(-25^{\frac{3}{2}}\)

    Rewrite in radical form.

    \(-(\sqrt{25})^{3}\)

    Simplify the radical.

    \(-(5)^{3}\)

    Simplify.

    \(-125\)

    b.

    \(-25^{-\frac{3}{2}}\)

    Rewrite using \(a^{-n}=\frac{1}{a^{n}}\).

    \(-\left(\frac{1}{25^{\frac{3}{2}}}\right)\)

    Rewrite in radical form.

    \(-\left(\frac{1}{(\sqrt{25})^{3}}\right)\)

    Simplify the radical.

    \(-\left(\frac{1}{(5)^{3}}\right)\)

    Simplify.

    \(-\frac{1}{125}\)

    c.

    \((-25)^{\frac{3}{2}}\)

    Rewrite in radical form.

    \((\sqrt{-25})^{3}\)

    There is no real number whose square root is \(-25\).

    Not a real number.

    Exercise \(\PageIndex{13}\)

    Simplify:

    1. \(-16^{\frac{3}{2}}\)
    2. \(-16^{-\frac{3}{2}}\)
    3. \((-16)^{-\frac{3}{2}}\)
    Answer
    1. \(-64\)
    2. \(-\frac{1}{64}\)
    3. Not a real number

    Exercise \(\PageIndex{14}\)

    Simplify:

    1. \(-81^{\frac{3}{2}}\)
    2. \(-81^{-\frac{3}{2}}\)
    3. \((-81)^{-\frac{3}{2}}\)
    Answer
    1. \(-729\)
    2. \(-\frac{1}{729}\)
    3. Not a real number

    Use the Properties of Exponents to Simplify Expressions with Rational Exponents

    The same properties of exponents that we have already used also apply to rational exponents. We will list the Properties of Exponents here to have them for reference as we simplify expressions.

    Properties of Exponents

    If \(a\) and \(b\) are real numbers and \(m\) and \(n\) are rational numbers, then

    Product Property

    \(a^{m} \cdot a^{n}=a^{m+n}\)

    Power Property

    \(\left(a^{m}\right)^{n}=a^{m \cdot n}\)

    Product to a Power

    \((a b)^{m}=a^{m} b^{m}\)

    Quotient Property

    \(\frac{a^{m}}{a^{n}}=a^{m-n}, a \neq 0\)

    Zero Exponent Definition

    \(a^{0}=1, a \neq 0\)

    Quotient to a Power Property

    \(\left(\frac{a}{b}\right)^{m}=\frac{a^{m}}{b^{m}}, b \neq 0\)

    Negative Exponent Property

    \(a^{-n}=\frac{1}{a^{n}}, a \neq 0\)

    We will apply these properties in the next example.

    Example \(\PageIndex{8}\)

    Simplify:

    1. \(x^{\frac{1}{2}} \cdot x^{\frac{5}{6}}\)
    2. \(\left(z^{9}\right)^{\frac{2}{3}}\)
    3. \(\frac{x^{\frac{1}{3}}}{x^{\frac{5}{3}}}\)

    Solution

    a. The Product Property tells us that when we multiple the same base, we add the exponents.

    \(x^{\frac{1}{2}} \cdot x^{\frac{5}{6}}\)

    The bases are the same, so we add the exponents.

    \(x^{\frac{1}{2}+\frac{5}{6}}\)

    Add the fractions.

    \(x^{\frac{8}{6}}\)

    Simplify the exponent.

    \(x^{\frac{4}{3}}\)

    b. The Power Property tells us that when we raise a power to a power, we multiple the exponents.

    \(\left(z^{9}\right)^{\frac{2}{3}}\)

    To raise a power to a power, we multiple the exponents.

    \(z^{9 \cdot \frac{2}{3}}\)

    Simplify.

    \(z^{6}\)

    c. The Quotient Property tells us that when we divide with the same base, we subtract the exponents.

    \(\frac{x^{\frac{1}{3}}}{x^{\frac{5}{3}}}\)

    To divide with the same base, we subtract the exponents.

    \(\frac{1}{x^{\frac{5}{3}-\frac{1}{3}}}\)

    Simplify.

    \(\frac{1}{x^{\frac{4}{3}}}\)

    Exercise \(\PageIndex{15}\)

    Simplify:

    1. \(x^{\frac{1}{6}} \cdot x^{\frac{4}{3}}\)
    2. \(\left(x^{6}\right)^{\frac{4}{3}}\)
    3. \(\frac{x^{\frac{2}{3}}}{x^{\frac{5}{3}}}\)
    Answer
    1. \(x^{\frac{3}{2}}\)
    2. \(x^{8}\)
    3. \(\frac{1}{x}\)

    Exercise \(\PageIndex{16}\)

    Simplify:

    1. \(y^{\frac{3}{4}} \cdot y^{\frac{5}{8}}\)
    2. \(\left(m^{9}\right)^{\frac{2}{9}}\)
    3. \(\frac{d^{\frac{1}{5}}}{d^{\frac{6}{5}}}\)
    Answer
    1. \(y^{\frac{11}{8}}\)
    2. \(m^{2}\)
    3. \(\frac{1}{d}\)

    Sometimes we need to use more than one property. In the next example, we will use both the Product to a Power Property and then the Power Property.

    Example \(\PageIndex{9}\)

    Simplify:

    1. \(\left(27 u^{\frac{1}{2}}\right)^{\frac{2}{3}}\)
    2. \(\left(m^{\frac{2}{3}} n^{\frac{1}{2}}\right)^{\frac{3}{2}}\)

    Solution:

    a.

    \(\left(27 u^{\frac{1}{2}}\right)^{\frac{2}{3}}\)

    First we use the Product to a Power Property.

    \((27)^{\frac{2}{3}}\left(u^{\frac{1}{2}}\right)^{\frac{2}{3}}\)

    Rewrite \(27\) as a power of \(3\).

    \(\left(3^{3}\right)^{\frac{2}{3}}\left(u^{\frac{1}{2}}\right)^{\frac{2}{3}}\)

    To raise a power to a power, we multiple the exponents.

    \(\left(3^{2}\right)\left(u^{\frac{1}{3}}\right)\)

    Simplify.

    \(9 u^{\frac{1}{3}}\)

    b.

    \(\left(m^{\frac{2}{3}} n^{\frac{1}{2}}\right)^{\frac{3}{2}}\)

    First we use the Product to a Power Property.

    \(\left(m^{\frac{2}{3}}\right)^{\frac{3}{2}}\left(n^{\frac{1}{2}}\right)^{\frac{3}{2}}\)

    To raise a power to a power, we multiply the exponents.

    \(m n^{\frac{3}{4}}\)

    Exercise \(\PageIndex{17}\)

    Simplify:

    1. \(\left(32 x^{\frac{1}{3}}\right)^{\frac{3}{5}}\)
    2. \(\left(x^{\frac{3}{4}} y^{\frac{1}{2}}\right)^{\frac{2}{3}}\)
    Answer
    1. \(8 x^{\frac{1}{5}}\)
    2. \(x^{\frac{1}{2}} y^{\frac{1}{3}}\)

    Exercise \(\PageIndex{18}\)

    Simplify:

    1. \(\left(81 n^{\frac{2}{5}}\right)^{\frac{3}{2}}\)
    2. \(\left(a^{\frac{3}{2}} b^{\frac{1}{2}}\right)^{\frac{4}{3}}\)
    Answer
    1. \(729 n^{\frac{3}{5}}\)
    2. \(a^{2} b^{\frac{2}{3}}\)

    We will use both the Product Property and the Quotient Property in the next example.

    Example \(\PageIndex{10}\)

    Simplify:

    1. \(\frac{x^{\frac{3}{4}} \cdot x^{-\frac{1}{4}}}{x^{-\frac{6}{4}}}\)
    2. \(\left(\frac{16 x^{\frac{4}{3}} y^{-\frac{5}{6}}}{x^{-\frac{2}{3}} y^{\frac{1}{6}}}\right)^{\frac{1}{2}}\)

    Solution:

    a.

    \(\frac{x^{\frac{3}{4}} \cdot x^{-\frac{1}{4}}}{x^{-\frac{6}{4}}}\)

    Use the Product Property in the numerator, add the exponents.

    \(\frac{x^{\frac{2}{4}}}{x^{-\frac{6}{4}}}\)

    Use the Quotient Property, subtract the exponents.

    \(x^{\frac{8}{4}}\)

    Simplify.

    \(x^{2}\)

    b.

    \(\left(\frac{16 x^{\frac{4}{3}} y^{-\frac{5}{6}}}{x^{-\frac{2}{3}} y^{\frac{1}{6}}}\right)^{\frac{1}{2}}\)

    Use the Quotient Property, subtract the exponents.

    \(\left(\frac{16 x^{\frac{6}{3}}}{y^{\frac{6}{6}}}\right)^{\frac{1}{2}}\)

    Simplify.

    \(\left(\frac{16 x^{2}}{y}\right)^{\frac{1}{2}}\)

    Use the Product to a Power Property, multiply the exponents.

    \(\frac{4 x}{y^{\frac{1}{2}}}\)

    Exercise \(\PageIndex{19}\)

    Simplify:

    1. \(\frac{m^{\frac{2}{3}} \cdot m^{-\frac{1}{3}}}{m^{-\frac{5}{3}}}\)
    2. \(\left(\frac{25 m^{\frac{1}{6}} n^{\frac{11}{6}}}{m^{\frac{2}{3}} n^{-\frac{1}{6}}}\right)^{\frac{1}{2}}\)
    Answer
    1. \(m^{2}\)
    2. \(\frac{5 n}{m^{\frac{1}{4}}}\)

    Exercise \(\PageIndex{20}\)

    Simplify:

    1. \(\frac{u^{\frac{4}{5}} \cdot u^{-\frac{2}{5}}}{u^{-\frac{13}{5}}}\)
    2. \(\left(\frac{27 x^{\frac{4}{5}} y^{\frac{1}{6}}}{x^{\frac{1}{5}} y^{-\frac{5}{6}}}\right)^{\frac{1}{3}}\)
    Answer
    1. \(u^{3}\)
    2. \(3 x^{\frac{1}{5}} y^{\frac{1}{3}}\)

    Access these online resources for additional instruction and practice with simplifying rational exponents.

    • Review-Rational Exponents
    • Using Laws of Exponents on Radicals: Properties of Rational Exponents

    Key Concepts

    • Rational Exponent \(a^{\frac{1}{n}}\)
      • If \(\sqrt[n]{a}\) is a real number and \(n≥2\), then \(a^{\frac{1}{n}}=\sqrt[n]{a}\).
    • Rational Exponent \(a^{\frac{m}{n}}\)
      • For any positive integers \(m\) and \(n\),
        \(a^{\frac{m}{n}}=(\sqrt[n]{a})^{m} \text { and } a^{\frac{m}{n}}=\sqrt[n]{a^{m}}\)
    • Properties of Exponents
      • If \(a, b\) are real numbers and \(m, n\) are rational numbers, then
        • Product Property \(a^{m} \cdot a^{n}=a^{m+n}\)
        • Power Property \(\left(a^{m}\right)^{n}=a^{m \cdot n}\)
        • Product to a Power \((a b)^{m}=a^{m} b^{m}\)
        • Quotient Property \(\frac{a^{m}}{a^{n}}=a^{m-n}, a \neq 0\)
        • Zero Exponent Definition \(a^{0}=1, a \neq 0\)
        • Quotient to a Power Property \(\left(\frac{a}{b}\right)^{m}=\frac{a^{m}}{b^{m}}, b \neq 0\)
        • Negative Exponent Property \(a^{-n}=\frac{1}{a^{n}}, a \neq 0\)

    How do you solve radicals and rational exponents?

    Given an expression with a rational exponent, write the expression as a radical. Determine the power by looking at the numerator of the exponent. Determine the root by looking at the denominator of the exponent. Using the base as the radicand, raise the radicand to the power and use the root as the index.

    What is rational exponent and radical expression?

    Square roots are most often written using a radical sign, like this, √4 . But there is another way to represent them. You can use rational exponents instead of a radical. A rational exponent is an exponent that is a fraction. For example, √4 can be written as 412 4 1 2 .