Back to Elementary Algebra 2e

7.6 Quadratic Equations

The Zero Product Property, which turns a factored equation into simple linear pieces and makes area and consecutive-integer word problems solvable.

Elementary Algebra 2e, 7.6 Quadratic Equations

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121 exercises

7.6 Exercise 1

Before you get started, take this readiness quiz.

Solve: 5y−3=05 y - 3 = 0.
If you missed this problem, review the reference.

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7.6 Exercise 2

Solve: 10a=010 a = 0.
If you missed this problem, review the reference.

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7.6 Exercise 3

Combine like terms: 12x2−6x+4x12 x^{2} - 6 x + 4 x.
If you missed this problem, review the reference.

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7.6 Exercise 4

Factor n3−9n2−22nn^{3} - 9 n^{2} - 22 n completely.
If you missed this problem, review the reference.

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7.6 Exercise 6

Solve: (x−3)(x+5)=0\left(x - 3\right) \left(x + 5\right) = 0.

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7.6 Exercise 7

Solve: (y−6)(y+9)=0\left(y - 6\right) \left(y + 9\right) = 0.

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7.6 Exercise 9

Solve: (3m−2)(2m+1)=0\left(3 m - 2\right) \left(2 m + 1\right) = 0.

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7.6 Exercise 10

Solve: (4p+3)(4p−3)=0\left(4 p + 3\right) \left(4 p - 3\right) = 0.

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7.6 Exercise 12

Solve: 2u(5u−1)=02 u \left(5 u - 1\right) = 0.

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7.6 Exercise 13

Solve: w(2w+3)=0w \left(2 w + 3\right) = 0.

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7.6 Exercise 15

Solve: (x+1)2=0\left(x + 1\right)^{2} = 0.

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7.6 Exercise 16

Solve: (v−2)2=0\left(v - 2\right)^{2} = 0.

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7.6 Exercise 18

Solve: x2−x−12=0x^{2} - x - 12 = 0.

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7.6 Exercise 19

Solve: b2+9b+14=0b^{2} + 9 b + 14 = 0.

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7.6 Exercise 21

Solve: 3c2=10c−83 c^{2} = 10 c - 8.

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7.6 Exercise 22

Solve: 2d2−5d=32 d^{2} - 5 d = 3.

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7.6 Exercise 24

Solve: 6a2+9a=3a6 a^{2} + 9 a = 3 a.

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7.6 Exercise 25

Solve: 45b2−2b=−17b45 b^{2} - 2 b = −17 b.

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7.6 Exercise 27

Solve: 25p2=4925 p^{2} = 49.

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7.6 Exercise 28

Solve: 36x2=12136 x^{2} = 121.

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7.6 Exercise 29

Solve: (3x−8)(x−1)=3x\left(3 x - 8\right) \left(x - 1\right) = 3 x.

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7.6 Exercise 30

Solve: (2m+1)(m+3)=12m\left(2 m + 1\right) \left(m + 3\right) = 12 m.

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7.6 Exercise 31

Solve: (k+1)(k−1)=8\left(k + 1\right) \left(k - 1\right) = 8.

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7.6 Exercise 33

Solve: 8x3=24x2−18x8 x^{3} = 24 x^{2} - 18 x.

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7.6 Exercise 34

Solve: 16y2=32y3+2y16 y^{2} = 32 y^{3} + 2 y.

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7.6 Exercise 35

Solve: 4x2=16x+844 x^{2} = 16 x + 84.

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7.6 Exercise 36

Solve: 18a2−30=−33a18 a^{2} - 30 = −33 a.

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7.6 Exercise 37

Solve: 123b=−6−60b2123 b = −6 - 60 b^{2}.

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7.6 Exercise 38

The product of two consecutive integers is 132. Find the integers.

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7.6 Exercise 39

The product of two consecutive integers is 240240. Find the integers.

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7.6 Exercise 40

The product of two consecutive integers is 420420. Find the integers.

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7.6 Exercise 42

A rectangular sign has an area of 30 square feet. The length of the sign is one foot more than the width. Find the length and width of the sign.

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7.6 Exercise 43

A rectangular patio has an area of 180 square feet. The width of the patio is three feet less than the length. Find the length and width of the patio.

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7.6 Exercise 45

A boat’s sail is a right triangle. The length of one side of the sail is 7 feet more than the other side. The hypotenuse is 13. Find the lengths of the two sides of the sail.

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7.6 Exercise 46

A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg.

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7.6 Exercise 47

Solve.

(x−3)(x+7)=0\left(x - 3\right) \left(x + 7\right) = 0

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7.6 Exercise 49

Solve.

(3a−10)(2a−7)=0\left(3 a - 10\right) \left(2 a - 7\right) = 0

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7.6 Exercise 51

Solve.

6m(12m−5)=06 m \left(12 m - 5\right) = 0

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7.6 Exercise 53

Solve.

(y−3)2=0\left(y - 3\right)^{2} = 0

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7.6 Exercise 55

Solve.

(2x−1)2=0\left(2 x - 1\right)^{2} = 0

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7.6 Exercise 57

Solve.

x2+7x+12=0x^{2} + 7 x + 12 = 0

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7.6 Exercise 59

Solve.

5a2−26a=245 a^{2} - 26 a = 24

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7.6 Exercise 61

Solve.

4m2=17m−154 m^{2} = 17 m - 15

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7.6 Exercise 63

Solve.

7a2+14a=7a7 a^{2} + 14 a = 7 a

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7.6 Exercise 65

Solve.

49m2=14449 m^{2} = 144

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7.6 Exercise 67

Solve.

(y−3)(y+2)=4y\left(y - 3\right) \left(y + 2\right) = 4 y

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7.6 Exercise 69

Solve.

(2x+1)(x−3)=−4x\left(2 x + 1\right) \left(x - 3\right) = −4 x

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7.6 Exercise 71

Solve.

16p3=24p2-9p16 p^{3} = 24 p^{2} - 9 p

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7.6 Exercise 73

Solve.

20x2−60x=−4520 x^{2} - 60 x = −45

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7.6 Exercise 75

Solve.

The product of two consecutive integers is 56. Find the integers.

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7.6 Exercise 77

Solve.

The area of a rectangular carpet is 28 square feet. The length is three feet more than the width. Find the length and the width of the carpet.

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7.6 Exercise 79

Solve.

A pennant is shaped like a right triangle, with hypotenuse 10 feet. The length of one side of the pennant is two feet longer than the length of the other side. Find the length of the two sides of the pennant.

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7.6 Exercise 81

Solve.

(x+8)(x−3)=0\left(x + 8\right) \left(x - 3\right) = 0

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7.6 Exercise 83

Solve.

p2+12p+11=0p^{2} + 12 p + 11 = 0

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7.6 Exercise 85

Solve.

m2=6m+16m^{2} = 6 m + 16

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7.6 Exercise 87

Solve.

a3−a2−42a=0a^{3} - a^{2} - 42 a = 0

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7.6 Exercise 89

Solve.

The product of two consecutive integers is 110. Find the integers.

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7.6 Exercise 91

Area of a patio If each side of a square patio is increased by 4 feet, the area of the patio would be 196 square feet. Solve the equation (s+4)2=196\left(s + 4\right)^{2} = 196 for s to find the length of a side of the patio.

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7.6 Exercise 93

Explain how you solve a quadratic equation. How many answers do you expect to get for a quadratic equation?

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7.6 Exercise 95

Find the greatest common factor.

42,6042 , 60

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7.6 Exercise 97

Find the greatest common factor.

90,150,10590 , 150 , 105

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7.6 Exercise 99

Factor the greatest common factor from each polynomial.

24x−4224 x - 42

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7.6 Exercise 101

Factor the greatest common factor from each polynomial.

15m4+6m2n15 m^{4} + 6 m^{2} n

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7.6 Exercise 103

Factor by grouping.

ax−ay+bx−bya x - a y + b x - b y

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7.6 Exercise 105

Factor by grouping.

x2+7x−3x−21x^{2} + 7 x - 3 x - 21

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7.6 Exercise 107

Factor by grouping.

m3+m2+m+1m^{3} + m^{2} + m + 1

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7.6 Exercise 109

Factor each trinomial of the form x2+bx+cx^{2} + b x + c.

u2+17u+72u^{2} + 17 u + 72

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7.6 Exercise 111

Factor each trinomial of the form x2+bx+cx^{2} + b x + c.

k2−16k+60k^{2} - 16 k + 60

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7.6 Exercise 113

Factor each trinomial of the form x2+bx+cx^{2} + b x + c.

y2+6y−7y^{2} + 6 y - 7

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7.6 Exercise 115

Factor each trinomial of the form x2+bx+cx^{2} + b x + c.

s2−2s−8s^{2} - 2 s - 8

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7.6 Exercise 117

In the following examples, factor each trinomial of the form x2+bxy+cy2x^{2} + b x y + c y^{2}.

x2+12xy+35y2x^{2} + 12 x y + 35 y^{2}

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7.6 Exercise 119

In the following examples, factor each trinomial of the form x2+bxy+cy2x^{2} + b x y + c y^{2}.

a2+4ab−21b2a^{2} + 4 a b - 21 b^{2}

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7.6 Exercise 121

Identify the best method to use to factor each polynomial.

y2−17y+42y^{2} - 17 y + 42

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7.6 Exercise 123

Identify the best method to use to factor each polynomial.

8a3+72a8 a^{3} + 72 a

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7.6 Exercise 125

Factor completely.

6x2+42x+606 x^{2} + 42 x + 60

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7.6 Exercise 127

Factor completely.

3n4−12n3−96n23 n^{4} - 12 n^{3} - 96 n^{2}

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7.6 Exercise 129

Factor.

2x2+9x+42 x^{2} + 9 x + 4

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7.6 Exercise 131

Factor.

18a2−9a+118 a^{2} - 9 a + 1

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7.6 Exercise 133

Factor.

15p2+2p−815 p^{2} + 2 p - 8

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7.6 Exercise 135

Factor.

40s2−s−640 s^{2} - s - 6

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7.6 Exercise 137

Factor.

3x2+3x−363 x^{2} + 3 x - 36

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7.6 Exercise 139

Factor.

60y2−85y−2560 y^{2} - 85 y - 25

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7.6 Exercise 141

Factor.

25x2+30x+925 x^{2} + 30 x + 9

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7.6 Exercise 143

Factor.

36a2−84ab+49b236 a^{2} - 84 a b + 49 b^{2}

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7.6 Exercise 145

Factor.

40x2+360x+81040 x^{2} + 360 x + 810

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7.6 Exercise 147

Factor.

2y3−16y2+32y2 y^{3} - 16 y^{2} + 32 y

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7.6 Exercise 149

Factor.

81r2−2581 r^{2} - 25

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7.6 Exercise 151

Factor.

169m2−n2169 m^{2} - n^{2}

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7.6 Exercise 153

Factor.

25p2−125 p^{2} - 1

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7.6 Exercise 155

Factor.

9−121y29 - 121 y^{2}

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7.6 Exercise 157

Factor.

20x2−12520 x^{2} - 125

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7.6 Exercise 159

Factor.

49u3−9u49 u^{3} - 9 u

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7.6 Exercise 161

Factor.

a3−125a^{3} - 125

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7.6 Exercise 163

Factor.

2m3+542 m^{3} + 54

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7.6 Exercise 165

Factor completely.

24x3+44x224 x^{3} + 44 x^{2}

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7.6 Exercise 167

Factor completely.

16n2−56mn+49m216 n^{2} - 56 m n + 49 m^{2}

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7.6 Exercise 169

Factor completely.

5r2+22r−485 r^{2} + 22 r - 48

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7.6 Exercise 171

Factor completely.

n4−81n^{4} - 81

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7.6 Exercise 173

Factor completely.

5x2+5x−605 x^{2} + 5 x - 60

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7.6 Exercise 175

Factor completely.

m3+125m^{3} + 125

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7.6 Exercise 177

Solve.

(a−3)(a+7)=0\left(a - 3\right) \left(a + 7\right) = 0

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7.6 Exercise 179

Solve.

3m(2m−5)(m+6)=03 m \left(2 m - 5\right) \left(m + 6\right) = 0

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7.6 Exercise 181

Solve.

x2+9x+20=0x^{2} + 9 x + 20 = 0

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7.6 Exercise 183

Solve.

2p2−11p=402 p^{2} - 11 p = 40

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7.6 Exercise 185

Solve.

144m2−25=0144 m^{2} - 25 = 0

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7.6 Exercise 187

Solve.

The product of two consecutive numbers is 462462. Find the numbers.

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7.6 Exercise 189

Find the Greatest Common Factor in each expression.

14y−4214 y - 42

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7.6 Exercise 191

Find the Greatest Common Factor in each expression.

80a2+120a380 a^{2} + 120 a^{3}

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7.6 Exercise 193

Factor completely.

x2+13x+42x^{2} + 13 x + 42

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7.6 Exercise 195

Factor completely.

3a3−6a2−72a3 a^{3} - 6 a^{2} - 72 a

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7.6 Exercise 197

Factor completely.

5n2+30n+455 n^{2} + 30 n + 45

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7.6 Exercise 199

Factor completely.

xy−8y+7x−56x y - 8 y + 7 x - 56

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7.6 Exercise 201

Factor completely.

9s2−12s+49 s^{2} - 12 s + 4

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7.6 Exercise 203

Factor completely.

100−a2100 - a^{2}

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7.6 Exercise 205

Factor completely.

3x2−75y23 x^{2} - 75 y^{2}

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7.6 Exercise 207

Factor completely.

ab−3b−2a+6a b - 3 b - 2 a + 6

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7.6 Exercise 209

Factor completely.

8m2+22m+58 m^{2} + 22 m + 5

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7.6 Exercise 211

Solve.

y2=y+132y^{2} = y + 132

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7.6 Exercise 213

Solve.

9b2−9=09 b^{2} - 9 = 0

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7.6 Exercise 215

Solve.

4n2+19n+21=04 n^{2} + 19 n + 21 = 0

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7.6 Exercise 217

Solve.

The product of two consecutive integers is 156. Find the integers.

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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.