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9.8E: Exercises

  • Page ID
    30282
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    Practice Makes Perfect

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

    In the following exercises, write as a radical expression.

    Example \(\PageIndex{47}\)
    1. \(x^{\frac{1}{2}}\)
    2. \(y^{\frac{1}{3}}\)
    3. \(z^{\frac{1}{4}}\)
    Example \(\PageIndex{48}\)
    1. \(r^{\frac{1}{2}}\)
    2. \(s^{\frac{1}{3}}\)
    3. \(t^{\frac{1}{4}}\)
    Answer
    1. \(\sqrt{r}\)
    2. \(\sqrt[3]{s}\)
    3. \(\sqrt[4]{t}\)
    Example \(\PageIndex{49}\)
    1. \(u^{\frac{1}{5}}\)
    2. \(v^{\frac{1}{9}}\)
    3. \(w^{\frac{1}{20}}\)
    Example \(\PageIndex{50}\)
    1. \(g^{\frac{1}{7}}\)
    2. \(h^{\frac{1}{5}}\)
    3. \(j^{\frac{1}{25}}\)
    Answer
    1. \(\sqrt[7]{g}\)
    2. \(\sqrt[5]{h}\)
    3. \(\sqrt[25]{j}\)
    In the following exercises, write with a rational exponent.
    Example \(\PageIndex{51}\)
    1. \(−\sqrt[7]{x}\)
    2. \(\sqrt[9]{y}\)
    3. \(\sqrt[5]{f}\)
    Example \(\PageIndex{52}\)
    1. \(\sqrt[8]{r}\)
    2. \(\sqrt[10]{s}\)
    3. \(\sqrt[4]{t}\)
    Answer
    1. \(r^{\frac{1}{8}}\)
    2. \(s^{\frac{1}{10}}\)
    3. \(t^{\frac{1}{4}}\)
    Example \(\PageIndex{53}\)
    1. \(\sqrt[3]{a}\
    2. \(\sqrt[12]{b}\)
    3. \(\sqrt{c}\)
    Example \(\PageIndex{54}\)
    1. \(\sqrt[5]{u}\)
    2. \(\sqrt{v}\)

    .

    Answer
    1. \(u^{\frac{1}{5}}\)
    2. \(v^{\frac{1}{2}}\)
    3. \(w^{\frac{1}{16}}\)
    Example \(\PageIndex{55}\)
    1. \(\sqrt[3]{7c}\)
    2. \(\sqrt[7]{12d}\)
    3. \(3\sqrt[4]{5f}\)
    Example \(\PageIndex{56}\)
    1. \(\sqrt[4]{5x}\)
    2. \(\sqrt[8]{9y}\)
    3. \(7\sqrt[5]{3z}\)
    Answer
    1. \((5x)^{\frac{1}{4}}\)
    2. \((9y)^{\frac{1}{8}}\)
    3. \(7(3z)^{\frac{1}{5}}\)
    Example \(\PageIndex{57}\)
    1. \(\sqrt{21p}\)
    2. \(\sqrt[4]{8q}\)
    3. \(\sqrt[6]{436r}\)
    Example \(\PageIndex{58}\)
    1. \(\sqrt[3]{25a}\)
    2. \(\sqrt{3b}\)

    .

    Answer
    1. \((25a)^{\frac{1}{3}}\)
    2. \((3b)^{\frac{1}{2}}\)
    3. \((40c)^{\frac{1}{10}}\)

    In the following exercises, simplify.

    Example \(\PageIndex{59}\)
    1. \(81^{\frac{1}{2}}\)
    2. \(125^{\frac{1}{3}}\)
    3. \(64^{\frac{1}{2}}\)
    Example \(\PageIndex{60}\)
    1. \(625^{\frac{1}{4}}\)
    2. \(243^{\frac{1}{5}}\)
    3. \(32^{\frac{1}{5}}\)
    Answer
    1. 5
    2. 3
    3. 2
    Example \(\PageIndex{61}\)
    1. \(16^{\frac{1}{4}}\)
    2. \(16^{\frac{1}{2}}\)
    3. \(3125^{\frac{1}{5}}\)
    Example \(\PageIndex{62}\)
    1. \(216^{\frac{1}{3}}\)
    2. \(32^{\frac{1}{5}}\)
    3. \(81^{\frac{1}{4}}\)
    Answer
    1. 6
    2. 2
    3. 3
    Example \(\PageIndex{63}\)
    1. \((−216)^{\frac{1}{3}}\)
    2. \(−216^{\frac{1}{3}}\)
    3. \((216)^{−\frac{1}{3}}\)
    Example \(\PageIndex{64}\)
    1. \((−243)^{\frac{1}{5}}\)
    2. \(−243^{\frac{1}{5}}\)
    3. \((243)^{−\frac{1}{5}}\)
    Answer
    1. −3
    2. −3
    3. \(\frac{1}{3}\)
    Example \(\PageIndex{65}\)
    1. \((−1)^{\frac{1}{3}}\)
    2. \(−1^{\frac{1}{3}}\)
    3. \((1)^{−\frac{1}{3}}\)
    Example \(\PageIndex{66}\)
    1. \((−1000)^{\frac{1}{3}}\)
    2. \(−1000^{\frac{1}{3}}\)
    3. \((1000)^{−\frac{1}{3}}\)
    Answer
    1. −10
    2. −10
    3. \(\frac{1}{10}
    Example \(\PageIndex{67}\)
    1. \((−81)^{\frac{1}{4}}\)
    2. \(−81^{\frac{1}{4}}\)
    3. \((81)^{−\frac{1}{4}}\)
    Example \(\PageIndex{68}\)
    1. \((−49)^{\frac{1}{2}}\)
    2. \(−49^{\frac{1}{2}}\)
    3. \((49)^{−\frac{1}{2}}\)
    Answer
    1. not a real number
    2. −7
    3. \(\frac{1}{7}\)
    Example \(\PageIndex{69}\)
    1. \((−36)^{\frac{1}{2}}\)
    2. \(−36^{\frac{1}{2}}\)
    3. \((36)^{−\frac{1}{2}}\)
    Example \(\PageIndex{70}\)
    1. \((−1)^{\frac{1}{4}}\)
    2. \((1)^{−\frac{1}{4}}\)
    3. \(−1^{\frac{1}{4}}\)
    Answer
    1. not a real number
    2. 1
    3. −1
    Example \(\PageIndex{71}\)
    1. \((−100)^{\frac{1}{2}}\)
    2. \(−100^{\frac{1}{2}}\)
    3. \((100)^{−\frac{1}{2}}\)
    Example \(\PageIndex{72}\)
    1. \((−32)^{\frac{1}{5}}\)
    2. \((243)^{−\frac{1}{5}}\)
    3. \(−125^{\frac{1}{3}}\)
    Answer
    1. −2
    2. \(\frac{1}{3}\)
    3. −5

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

    In the following exercises, write with a rational exponent.

    Example \(\PageIndex{73}\)
    1. \(\sqrt{m^5}\)
    2. \(\sqrt[3]{n^2}\)
    3. \(\sqrt[4]{p^3}\)
    Example \(\PageIndex{74}\)
    1. \(\sqrt[4]{r^7}\)
    2. \(\sqrt[5]{s^3}\)
    3. \(\sqrt[3]{t^7}\)
    Answer
    1. \(r^{\frac{7}{4}}\)
    2. \(s^{\frac{3}{5}}\)
    3. \(t^{\frac{7}{3}}\)
    Exercise \(\PageIndex{75}\)
    1. \(\sqrt[5]{u^2}\)
    2. \(\sqrt[5]{v^8}\)
    3. \(\sqrt[9]{w^4}\)
    Example \(\PageIndex{76}\)
    1. \(\sqrt[3]{a}\)
    2. \(\sqrt[5]{b}\)
    3. \(\sqrt[3]{c^5}\)
    Answer
    1. \(a^{\frac{1}{3}}\)
    2. \(b^{\frac{1}{5}}\)
    3. \(c^{\frac{5}{3}}\)
    In the following exercises, simplify.
    Example \(\PageIndex{77}\)
    1. \(16^{\frac{3}{2}}\)
    2. \(8^{\frac{2}{3}}\)
    3. \(10,000^{\frac{3}{4}}\)
    Example \(\PageIndex{78}\)
    1. \(1000^{\frac{2}{3}}\)
    2. \(25^{\frac{3}{2}}\)
    3. \(32^{\frac{3}{5}}\)
    Answer
    1. 100
    2. 125
    3. 8
    Example \(\PageIndex{79}\)
    1. \(275^{\frac{3}{2}}\)
    2. \(16^{\frac{5}{4}}\)
    3. \(32^{\frac{2}{5}}\)
    Example \(\PageIndex{80}\)
    1. \(16^{\frac{3}{2}}\)
    2. \(125^{\frac{5}{3}}\)
    3. \(64^{\frac{4}{3}}\)
    Answer
    1. 64
    2. 3125
    3. 256
    Example \(\PageIndex{81}\)
    1. \(32^{\frac{2}{5}}\)
    2. \(27^{−\frac{2}{3}}\)
    3. \(25^{−\frac{3}{2}}\)
    Example \(\PageIndex{82}\)
    1. \(64^{\frac{5}{2}}\)
    2. \(81^{−\frac{3}{2}}\)
    3. \(27^{−\frac{4}{3}}\)
    Answer
    1. 32,768
    2. \(\frac{1}{729}\)
    3. \(\frac{1}{81}\)
    Example \(\PageIndex{83}\)
    1. \(25^{\frac{3}{2}}\)
    2. \(9^{−\frac{3}{2}}\)
    3. \((−64)^{\frac{2}{3}}\)
    Example \(\PageIndex{84}\)
    1. \(100^{\frac{3}{2}}\)
    2. \(49^{−\frac{5}{2}}\)
    3. \((−100)^{\frac{3}{2}}\)
    Answer
    1. 1000
    2. \(\frac{1}{16,807}\)
    3. not a real numbe
    Example \(\PageIndex{85}\)
    1. \(−9^{\frac{3}{2}}\)
    2. \(−9^{−\frac{3}{2}}\)
    3. \((−9)^{\frac{3}{2}}\)
    Example \(\PageIndex{86}\)
    1. \(−64^{\frac{3}{2}}\)
    2. \(−64^{−\frac{3}{2}}\)
    3. \((−64)^{\frac{3}{2}}\)
    Answer
    1. −512
    2. \(−\frac{1}{512}\)
    3. not a real number
    Example \(\PageIndex{87}\)
    1. \(−100^{\frac{3}{2}}\)
    2. \(−100^{−\frac{3}{2}}\)
    3. \((−100)^{\frac{3}{2}}\)
    Example \(\PageIndex{88}\)
    1. \(−49^{\frac{3}{2}}\)
    2. \(−49^{−\frac{3}{2}}\)
    3. \((−49)^{\frac{3}{2}}\)
    Answer
    1. −343
    2. \(−\frac{1}{343}\)
    3. not a real number

    Use the Laws of Exponents to Simplify Expressions with Rational Exponents

    In the following exercises, simplify.

    Example \(\PageIndex{89}\)
    1. \(4^{\frac{5}{8}}·4^{\frac{11}{8}}\)
    2. \(m^{\frac{7}{12}}·m^{\frac{17}{12}}\)
    3. \(p^{\frac{3}{7}}·p^{\frac{18}{7}}\)
    Example \(\PageIndex{90}\)
    1. \(6^{\frac{5}{2}}·6^{\frac{12}{6}}\)
    2. \(n^{\frac{2}{10}}·n^{\frac{8}{10}}\)
    3. \(q^{\frac{2}{5}}·q^{\frac{13}{5}}\)
    Answer
    1. 216
    2. n
    3. \(q^3\)
    Example \(\PageIndex{91}\)
    1. \(5^{\frac{1}{2}}·5^{\frac{7}{2}}\)
    2. \(c^{\frac{3}{4}}·c^{\frac{9}{4}}\)
    3. \(d^{\frac{3}{5}}·d^{\frac{2}{5}}\)
    Example \(\PageIndex{92}\)
    1. \(10^{\frac{1}{3}}·10^{\frac{5}{3}}\)
    2. \(x^{\frac{5}{6}}·x^{\frac{7}{6}}\)
    3. \(y^{\frac{11}{8}}·y^{\frac{21}{8}}\)
    Answer
    1. 100
    2. \(x^2\)
    3. \(y^4\)
    Example \(\PageIndex{93}\)
    1. \((m^6)^{\frac{5}{2}}\)
    2. \((n^9)^{\frac{4}{3}}\)
    3. \((p^{12})^{\frac{3}{4}}\)
    Example \(\PageIndex{94}\)
    1. \((a^{12})^{\frac{1}{6}}\)
    2. \((b^{15})^{\frac{3}{5}}\)
    3. \((c^{11})^{\frac{1}{11}}\)
    Answer
    1. \(a^2\)
    2. \(b^9\)
    3. c
    Example \(\PageIndex{95}\)
    1. \((x^{12})^{\frac{2}{3}}\)
    2. \((y^{20})^{\frac{2}{5}}\)
    3. \((z^{16})^{\frac{1}{16}}\)
    Example \(\PageIndex{96}\)
    1. \((h^6)^{\frac{4}{3}}\)
    2. \((k^{12})^{\frac{3}{4}}\)
    3. \((j^{10})^{\frac{7}{5}}\)
    Answer
    1. \(h^8\)
    2. \(k^9\)
    3. \(j^{14}\)
    Example \(\PageIndex{97}\)
    1. \(\frac{x^{\frac{7}{2}}}{x^{\frac{5}{2}}}\)
    2. \(\frac{y^{\frac{5}{2}}}{y^{\frac{1}{2}}}\)
    3. \(\frac{r^{\frac{4}{5}}}{r^{\frac{9}{5}}}\)
    Example \(\PageIndex{98}\)
    1. \(\frac{s^{\frac{11}{5}}}{s^{\frac{6}{5}}}\)
    2. \(\frac{z^{\frac{7}{3}}}{z^{\frac{1}{3}}}\)
    3. \(\frac{w^{\frac{2}{7}}}{w^{\frac{9}{7}}}\)
    Answer
    1. s
    2. \(z^2\)
    3. \(\frac{1}{w}\)
    Example \(\PageIndex{99}\)
    1. \(\frac{t^{\frac{12}{5}}}{t^{\frac{7}{5}}}\)
    2. \(\frac{x^{\frac{3}{2}}}{x^{\frac{1}{2}}}\)
    3. \(\frac{m^{\frac{13}{8}}}{m^{\frac{5}{8}}}\)
    Example \(\PageIndex{100}\)
    1. \(\frac{u^{\frac{13}{9}}}{u^{\frac{4}{9}}}\)
    2. \(\frac{r^{\frac{15}{7}}}{r^{\frac{8}{7}}}\)
    3. \(\frac{n^{\frac{3}{5}}}{n^{\frac{8}{5}}}\)
    Answer
    1. u
    2. r
    3. \(\frac{1}{n}\)
    Example \(\PageIndex{101}\)
    1. \((9p^{\frac{2}{3}})^{\frac{5}{2}}\)
    2. \((27q^{\frac{3}{2}})^{\frac{4}{3}}\)​​​​​
    Example \(\PageIndex{102}\)
    1. \((81r^{\frac{4}{5}})^{\frac{1}{4}}\)
    2. \((64s^{\frac{3}{7}})^{\frac{1}{6}}\)
    Answer
    1. \(3r^{\frac{1}{5}}\)
    2. \(2s^{\frac{1}{14}}\)
    Example \(\PageIndex{103}\)
    1. \((16u^{\frac{1}{3}})^{\frac{3}{4}}\)
    2. \((100v^{\frac{2}{5}})^{\frac{3}{2}}\)
    Example \(\PageIndex{104}\)
    1. \((27m^{\frac{3}{4}})^{\frac{2}{3}}\)
    2. \((625n^{\frac{8}{3}})^{\frac{3}{4}}\)
    Answer
    1. \(9m^{\frac{1}{2}}\)
    2. \(125n^2\)
    Example \(\PageIndex{105}\)
    1. \((x^{8}y^{10})^{\frac{1}{2}}\)
    2. \((a^{9}by ^{12})^{\frac{1}{3}}\)
    Example \(\PageIndex{106}\)
    1. \((r^{8}s^{4})^{\frac{1}{4}}\)
    2. \((u^{15}v^{20})^{\frac{1}{5}}\)
    Answer
    1. \(r^{2}s\)
    2. \(u^{3}v^{4}\)
    Example \(\PageIndex{107}\)
    1. \((a^{6}b^{16})^{\frac{1}{2}}\)
    2. \((j^{9}k^{6})^{\frac{2}{3}}\)
    Example \(\PageIndex{108}\)
    1. \((r^{16}s^{10})^{\frac{1}{2}}\)
    2. \((u^{10}v^5)^{\frac{4}{5}}\)
    Answer
    1. \(r^{8}s^{5}\)
    2. \(u^{8}v^{4}\)
    Example \(\PageIndex{109}\)
    1. \(\frac{r^{\frac{5}{2}}·r^{−\frac{1}{2}}}{r^{−\frac{3}{2}}}\)
    2. \(\frac{s^{\frac{1}{5}}·s}{s^{−\frac{9}{5}}}\)
    Example \(\PageIndex{110}\)
    1. \(\frac{a^{\frac{3}{4}}·a^{−\frac{1}{4}}}{a^{−\frac{10}{4}}}\)
    2. \(\frac{b^{\frac{2}{3}}·b}{b^{−\frac{7}{3}}}\)
    Answer
    1. \(a^3\)
    2. \(b^4\)
    Example \(\PageIndex{111}\)
    1. \(\frac{c^{\frac{5}{3}}·c^{−\frac{1}{3}}}{c^{−\frac{2}{3}}}\)
    2. \(\frac{d^{\frac{3}{5}}·d}{d^{−\frac{2}{5}}}\)
    Example \(\PageIndex{112}\)
    1. \(\frac{m^{\frac{7}{4}}·m^{−\frac{5}{4}}}{m^{−\frac{2}{4}}}\)
    2. \(\frac{n^{\frac{3}{7}}·n}{n^{−\frac{4}{7}}}\)
    Answer
    1. m
    2. \(n^2\)
    Example \(\PageIndex{113}\)

    \(4^{\frac{5}{2}}·4^{\frac{1}{2}}\)

    Example \(\PageIndex{114}\)

    \(n^{\frac{2}{6}}·n^{\frac{4}{6}}\)

    Answer

    n

    Example \(\PageIndex{115}\)

    \((a^24)^ {\frac{1}{6}}\)

    Example \(\PageIndex{116}\)

    \((b^{10})^{\frac{3}{5}}\)

    Answer

    \(b^6\)

    Example \(\PageIndex{117}\)

    \(\frac{w^{\frac{2}{5}}}{w^{\frac{7}{5}}}\)

    Example \(\PageIndex{118}\)

    \(\frac{z^{\frac{2}{3}}}{z^{\frac{8}{3}}}\)

    Answer

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

    Example \(\PageIndex{119}\)

    \((27r^{\frac{3}{5}})^{\frac{1}{3}}\)

    Example \(\PageIndex{120}\)

    \((64s^{\frac{3}{5}})^{\frac{1}{6}}\)

    Answer

    \(2s^{\frac{1}{10}}\)

    Example \(\PageIndex{121}\)

    \((r^{9}s^{12})^{\frac{1}{3}}\)

    Example \(\PageIndex{122}\)

    \((u^{12}v^{18})^{\frac{1}{6}}\)

    Answer

    \(u^{2}v^{3}\)​​​​​​

    Everyday Math

    Example \(\PageIndex{123}\)

    Landscaping Joe wants to have a square garden plot in his backyard. He has enough compost to cover an area of 144 square feet. Simplify \(144^{\frac{1}{2}}\) to find the length of each side of his garden.

    Example \(\PageIndex{124}\)

    Landscaping Elliott wants to make a square patio in his yard. He has enough concrete to pave an area of 242 square feet. Simplify \(242^{\frac{1}{2}}\) to find the length of each side of his patio.Round to the nearest tenth of a foot.

    Answer

    15.6 feet

    Example \(\PageIndex{125}\)

    Gravity While putting up holiday decorations, Bob dropped a decoration from the top of a tree that is 12 feet tall. Simplify \(\frac{12^{\frac{1}{2}}}{16^{\frac{1}{2}}}\) to find how many seconds it took for the decoration to reach the ground. Round to the nearest tenth of a second.

    Example \(\PageIndex{126}\)

    Gravity An airplane dropped a flare from a height of 1024 feet above a lake. Simplify \(\frac{1024^{\frac{1}{2}}}{16^{\frac{1}{2}}}\) to find how many seconds it took for the flare to reach the water.

    Answer

    8 seconds

    Writing Exercises

    Example \(\PageIndex{127}\)

    Show two different algebraic methods to simplify \(4^{\frac{3}{2}}\). Explain all your steps.

    Example \(\PageIndex{128}\)

    Explain why the expression \((−16)^{\frac{3}{2}}\) cannot be evaluated.


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