Back to Elementary Algebra 2e

9.4 Multiply Square Roots

Multiplying radicands and simplifying what results, plus distributing, FOIL, and conjugate products applied to binomials containing radicals.

Elementary Algebra 2e, 9.4 Multiply Square Roots

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88 exercises

9.4 Exercise 1

Before you get started, take this readiness quiz.

Simplify: (3u)(8v)\left(3 u\right) \left(8 v\right).
If you missed this problem, review the reference.

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9.4 Exercise 2

Simplify: 6(12−7n)6 \left(12 - 7 n\right).
If you missed this problem, review the reference.

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9.4 Exercise 3

Simplify: (2+a)(4−a)\left(2 + a\right) \left(4 - a\right).
If you missed this problem, review the reference.

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9.4 Exercise 4

Simplify: ⓐ 2·6\sqrt{2} \cdot \sqrt{6} ⓑ (43)(212)\left(4 \sqrt{3}\right) \left(2 \sqrt{12}\right).

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9.4 Exercise 5

Simplify: ⓐ 3·6\sqrt{3} \cdot \sqrt{6} ⓑ (26)(312)\left(2 \sqrt{6}\right) \left(3 \sqrt{12}\right).

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9.4 Exercise 6

Simplify: ⓐ 5·10\sqrt{5} \cdot \sqrt{10} ⓑ (63)(56)\left(6 \sqrt{3}\right) \left(5 \sqrt{6}\right).

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9.4 Exercise 7

Simplify: (62)(310)\left(6 \sqrt{2}\right) \left(3 \sqrt{10}\right).

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9.4 Exercise 8

Simplify: (32)(230)\left(3 \sqrt{2}\right) \left(2 \sqrt{30}\right).

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9.4 Exercise 9

Simplify: (33)(36)\left(3 \sqrt{3}\right) \left(3 \sqrt{6}\right).

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9.4 Exercise 10

Simplify: ⓐ (8x3)(3x)\left(\sqrt{8 x^{3}}\right) \left(\sqrt{3 x}\right) ⓑ (20y2)(5y3)\left(\sqrt{20 y^{2}}\right) \left(\sqrt{5 y^{3}}\right).

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9.4 Exercise 11

Simplify: ⓐ (6x3)(3x)\left(\sqrt{6 x^{3}}\right) \left(\sqrt{3 x}\right) ⓑ (2y3)(50y2)\left(\sqrt{2 y^{3}}\right) \left(\sqrt{50 y^{2}}\right).

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9.4 Exercise 12

Simplify: ⓐ (6x5)(2x)\left(\sqrt{6 x^{5}}\right) \left(\sqrt{2 x}\right) ⓑ (12y2)(3y5)\left(\sqrt{12 y^{2}}\right) \left(\sqrt{3 y^{5}}\right).

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9.4 Exercise 13

Simplify: (106p3)(318p)\left(10 \sqrt{6 p^{3}}\right) \left(3 \sqrt{18 p}\right).

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9.4 Exercise 14

Simplify: (62x2)(845x4)\left(6 \sqrt{2 x^{2}}\right) \left(8 \sqrt{45 x^{4}}\right).

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9.4 Exercise 15

Simplify: (26y4)(1230y)\left(2 \sqrt{6 y^{4}}\right) \left(12 \sqrt{30 y}\right).

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9.4 Exercise 16

Simplify: ⓐ (2)2\left(\sqrt{2}\right)^{2} ⓑ (−11)2\left(− \sqrt{11}\right)^{2}.

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9.4 Exercise 17

Simplify: ⓐ (12)2\left(\sqrt{12}\right)^{2} ⓑ (−15)2\left(− \sqrt{15}\right)^{2}.

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9.4 Exercise 18

Simplify: ⓐ (16)2\left(\sqrt{16}\right)^{2} ⓑ (−20)2\left(− \sqrt{20}\right)^{2}.

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9.4 Exercise 19

Simplify: ⓐ (23)(83)\left(2 \sqrt{3}\right) \left(8 \sqrt{3}\right) ⓑ (36)2\left(3 \sqrt{6}\right)^{2}.

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9.4 Exercise 20

Simplify: ⓐ (611)(511)\left(6 \sqrt{11}\right) \left(5 \sqrt{11}\right) ⓑ (58)2\left(5 \sqrt{8}\right)^{2}.

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9.4 Exercise 21

Simplify: ⓐ (37)(107)\left(3 \sqrt{7}\right) \left(10 \sqrt{7}\right) ⓑ (−46)2\left(−4 \sqrt{6}\right)^{2}.

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9.4 Exercise 22

Simplify: ⓐ 3(5−2)3 \left(5 - \sqrt{2}\right) ⓑ 2(4−10)\sqrt{2} \left(4 - \sqrt{10}\right).

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9.4 Exercise 23

Simplify: ⓐ 2(3−5)2 \left(3 - \sqrt{5}\right) ⓑ 3(2−18)\sqrt{3} \left(2 - \sqrt{18}\right).

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9.4 Exercise 24

Simplify: ⓐ 6(2+6)6 \left(2 + \sqrt{6}\right) ⓑ 7(1+14)\sqrt{7} \left(1 + \sqrt{14}\right).

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9.4 Exercise 25

Simplify: ⓐ 5(7+25)\sqrt{5} \left(7 + 2 \sqrt{5}\right) ⓑ 6(2+18)\sqrt{6} \left(\sqrt{2} + \sqrt{18}\right).

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9.4 Exercise 26

Simplify: ⓐ 6(1+36)\sqrt{6} \left(1 + 3 \sqrt{6}\right) ⓑ 12(3+24)\sqrt{12} \left(\sqrt{3} + \sqrt{24}\right).

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9.4 Exercise 27

Simplify: ⓐ 8(2−58)\sqrt{8} \left(2 - 5 \sqrt{8}\right) ⓑ 14(2+42)\sqrt{14} \left(\sqrt{2} + \sqrt{42}\right).

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9.4 Exercise 28

Simplify: (2+3)(4−3)\left(2 + \sqrt{3}\right) \left(4 - \sqrt{3}\right).

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9.4 Exercise 29

Simplify: (1+6)(3−6)\left(1 + \sqrt{6}\right) \left(3 - \sqrt{6}\right).

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9.4 Exercise 30

Simplify: (4−10)(2+10)\left(4 - \sqrt{10}\right) \left(2 + \sqrt{10}\right).

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9.4 Exercise 31

Simplify: (3−27)(4−27)\left(3 - 2 \sqrt{7}\right) \left(4 - 2 \sqrt{7}\right).

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9.4 Exercise 32

Simplify: (6−37)(3+47)\left(6 - 3 \sqrt{7}\right) \left(3 + 4 \sqrt{7}\right).

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9.4 Exercise 33

Simplify: (2−311)(4−11)\left(2 - 3 \sqrt{11}\right) \left(4 - \sqrt{11}\right).

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9.4 Exercise 34

Simplify: (32−5)(2+45)\left(3 \sqrt{2} - \sqrt{5}\right) \left(\sqrt{2} + 4 \sqrt{5}\right).

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9.4 Exercise 35

Simplify: (53−7)(3+27)\left(5 \sqrt{3} - \sqrt{7}\right) \left(\sqrt{3} + 2 \sqrt{7}\right).

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9.4 Exercise 36

Simplify: (6−38)(26+8)\left(\sqrt{6} - 3 \sqrt{8}\right) \left(2 \sqrt{6} + \sqrt{8}\right)

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9.4 Exercise 37

Simplify: (4−2x)(1+3x)\left(4 - 2 \sqrt{x}\right) \left(1 + 3 \sqrt{x}\right).

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9.4 Exercise 38

Simplify: (6−5m)(2+3m)\left(6 - 5 \sqrt{m}\right) \left(2 + 3 \sqrt{m}\right).

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9.4 Exercise 39

Simplify: (10+3n)(1−5n)\left(10 + 3 \sqrt{n}\right) \left(1 - 5 \sqrt{n}\right).

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9.4 Exercise 41

Simplify: ⓐ (10+2)2\left(10 + \sqrt{2}\right)^{2} ⓑ (1+36)2\left(1 + 3 \sqrt{6}\right)^{2}.

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9.4 Exercise 42

Simplify: ⓐ (6−5)2\left(6 - \sqrt{5}\right)^{2} ⓑ (9−210)2\left(9 - 2 \sqrt{10}\right)^{2}.

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9.4 Exercise 44

Simplify: (2+5m)2\left(2 + 5 \sqrt{m}\right)^{2}.

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9.4 Exercise 45

Simplify: (3−4n)2\left(3 - 4 \sqrt{n}\right)^{2}.

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9.4 Exercise 47

Simplify: (2−3)(2+3)\left(2 - \sqrt{3}\right) \left(2 + \sqrt{3}\right).

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9.4 Exercise 48

Simplify: (1+5)(1−5)\left(1 + \sqrt{5}\right) \left(1 - \sqrt{5}\right).

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9.4 Exercise 50

Simplify: (3−25)(3+25)\left(3 - 2 \sqrt{5}\right) \left(3 + 2 \sqrt{5}\right).

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9.4 Exercise 51

Simplify: (4+57)(4−57)\left(4 + 5 \sqrt{7}\right) \left(4 - 5 \sqrt{7}\right).

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9.4 Exercise 52

Simplify.

ⓐ 2·8\sqrt{2} \cdot \sqrt{8} ⓑ (33)(218)\left(3 \sqrt{3}\right) \left(2 \sqrt{18}\right)

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9.4 Exercise 54

Simplify.

ⓐ 7·14\sqrt{7} \cdot \sqrt{14} ⓑ (48)(58)\left(4 \sqrt{8}\right) \left(5 \sqrt{8}\right)

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9.4 Exercise 56

Simplify.

(52)(36)\left(5 \sqrt{2}\right) \left(3 \sqrt{6}\right)

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9.4 Exercise 58

Simplify.

(−23)(318)\left(−2 \sqrt{3}\right) \left(3 \sqrt{18}\right)

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9.4 Exercise 60

Simplify.

(56)(−12)\left(5 \sqrt{6}\right) \left(− \sqrt{12}\right)

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9.4 Exercise 62

Simplify.

(−27)(−214)\left(−2 \sqrt{7}\right) \left(−2 \sqrt{14}\right)

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9.4 Exercise 64

Simplify.

ⓐ (15y)(5y3)\left(\sqrt{15 y}\right) \left(\sqrt{5 y^{3}}\right) ⓑ (2n2)(18n3)\left(\sqrt{2 n^{2}}\right) \left(\sqrt{18 n^{3}}\right)

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9.4 Exercise 66

Simplify.

ⓐ (16y2)(8y4)\left(\sqrt{16 y^{2}}\right) \left(\sqrt{8 y^{4}}\right) ⓑ (11s6)(11s)\left(\sqrt{11 s^{6}}\right) \left(\sqrt{11 s}\right)

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9.4 Exercise 68

Simplify.

(25b3)(415b)\left(2 \sqrt{5 b^{3}}\right) \left(4 \sqrt{15 b}\right)

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9.4 Exercise 70

Simplify.

(52d7)(350d3)\left(5 \sqrt{2 d^{7}}\right) \left(3 \sqrt{50 d^{3}}\right)

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9.4 Exercise 72

Simplify.

34y439y5\left(3 \sqrt{4 y^{4}}\right) \left(3 \sqrt{9 y^{5}}\right)

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9.4 Exercise 74

Simplify.

(42k5)(−332k6)\left(4 \sqrt{2 k^{5}}\right) \left(−3 \sqrt{32 k^{6}}\right)

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9.4 Exercise 76

Simplify.

ⓐ (11)2\left(\sqrt{11}\right)^{2} ⓑ (−21)2\left(− \sqrt{21}\right)^{2}

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9.4 Exercise 78

Simplify.


ⓐ (23)2\left(\sqrt{23}\right)^{2}
ⓑ (−3)2\left(− \sqrt{3}\right)^{2}

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9.4 Exercise 80

Simplify.

ⓐ (213)(−913)\left(2 \sqrt{13}\right) \left(−9 \sqrt{13}\right) ⓑ (65)2\left(6 \sqrt{5}\right)^{2}

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9.4 Exercise 82

Simplify.

ⓐ (−75)(−310)\left(−7 \sqrt{5}\right) \left(−3 \sqrt{10}\right) ⓑ (−214)2\left(−2 \sqrt{14}\right)^{2}

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9.4 Exercise 84

Simplify.

ⓐ 4(6−11)4 \left(6 - \sqrt{11}\right) ⓑ 2(5−12)\sqrt{2} \left(5 - \sqrt{12}\right)

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9.4 Exercise 86

Simplify.

ⓐ 7(−2−11)7 \left(−2 - \sqrt{11}\right) ⓑ 7(6−14)\sqrt{7} \left(6 - \sqrt{14}\right)

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9.4 Exercise 88

Simplify.

ⓐ 11(8+411)\sqrt{11} \left(8 + 4 \sqrt{11}\right) ⓑ 3(12+27)\sqrt{3} \left(\sqrt{12} + \sqrt{27}\right)

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9.4 Exercise 90

Simplify.

ⓐ 2(−5+92)\sqrt{2} \left(−5 + 9 \sqrt{2}\right) ⓑ 7(3−21)\sqrt{7} \left(\sqrt{3} - \sqrt{21}\right)

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9.4 Exercise 92

Simplify.

(7+3)(9−3)\left(7 + \sqrt{3}\right) \left(9 - \sqrt{3}\right)

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9.4 Exercise 94

Simplify.

(9−2)(6+2)\left(9 - \sqrt{2}\right) \left(6 + \sqrt{2}\right)

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9.4 Exercise 96

Simplify.

(5−7)(4−7)\left(5 - \sqrt{7}\right) \left(4 - \sqrt{7}\right)

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9.4 Exercise 98

Simplify.

(7−25)(4+95)\left(7 - 2 \sqrt{5}\right) \left(4 + 9 \sqrt{5}\right)

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9.4 Exercise 100

Simplify.

(11+5)(11+65)\left(\sqrt{11} + \sqrt{5}\right) \left(\sqrt{11} + 6 \sqrt{5}\right)

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9.4 Exercise 102

Simplify.

(46+713)(86−313)\left(4 \sqrt{6} + 7 \sqrt{13}\right) \left(8 \sqrt{6} - 3 \sqrt{13}\right)

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9.4 Exercise 104

Simplify.

(9−w)(2+w)\left(9 - \sqrt{w}\right) \left(2 + \sqrt{w}\right)

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9.4 Exercise 106

Simplify.

(6+5n)(11+3n)\left(6 + 5 \sqrt{n}\right) \left(11 + 3 \sqrt{n}\right)

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9.4 Exercise 108

Simplify.

ⓐ (4+11)2\left(4 + \sqrt{11}\right)^{2} ⓑ (3−25)2\left(3 - 2 \sqrt{5}\right)^{2}

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9.4 Exercise 110

Simplify.

ⓐ (5−10)2\left(5 - \sqrt{10}\right)^{2} ⓑ (8+32)2\left(8 + 3 \sqrt{2}\right)^{2}

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9.4 Exercise 112

Simplify.

(10−3)(10+3)\left(10 - \sqrt{3}\right) \left(10 + \sqrt{3}\right)

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9.4 Exercise 114

Simplify.

(7+10)(7−10)\left(7 + \sqrt{10}\right) \left(7 - \sqrt{10}\right)

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9.4 Exercise 116

Simplify.

(1+82)(1−82)\left(1 + 8 \sqrt{2}\right) \left(1 - 8 \sqrt{2}\right)

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9.4 Exercise 118

Simplify.

(9−43)(9+43)\left(9 - 4 \sqrt{3}\right) \left(9 + 4 \sqrt{3}\right)

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9.4 Exercise 120

Simplify.

(46)(−18)\left(4 \sqrt{6}\right) \left(− \sqrt{18}\right)

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9.4 Exercise 122

Simplify.

(−57)(621)\left(−5 \sqrt{7}\right) \left(6 \sqrt{21}\right)

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9.4 Exercise 124

Simplify.

(35y3)(7y3)\left(\sqrt{35 y^{3}}\right) \left(\sqrt{7 y^{3}}\right)

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9.4 Exercise 126

Simplify.

(29)2\left(\sqrt{29}\right)^{2}

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9.4 Exercise 128

Simplify.

(−4+17)(−3+17)\left(−4 + \sqrt{17}\right) \left(−3 + \sqrt{17}\right)

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9.4 Exercise 132

A garden will be made so as to contain two square sections, one section with side length 5+6\sqrt{5} + \sqrt{6} yards and one section with side length 2+3\sqrt{2} + \sqrt{3} yards. Simplify 5+62+2+32\left(\sqrt{5} + \sqrt{6}\right)^{2} + \left(\sqrt{2} + \sqrt{3}\right)^{2} to determine the total area of the garden. Round your answer to the nearest tenth.

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9.4 Exercise 134

  1. ⓐ Explain why (−n)2\left(− \sqrt{n}\right)^{2} is always positive, for n≥0n \geq 0.
  2. ⓑ Explain why −n2- \left(\sqrt{n}\right)^{2} is always negative, for n≥0n \geq 0.
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Adapted from Elementary Algebra 2e © 2020 Rice University. Licensed under CC BY 4.0. Source: Elementary Algebra 2e. Imported at revision 77a933c.