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Beginning and Intermediate Algebra

Margaret L. Lial, John Hornsby, Terry McGinnis

Chapter 11

Quadratic Equations, Inequalities, and Functions - all with Video Answers

Educators


Section 1

Solving Quadratic Equations by the Square Root Property

00:40

Problem 1

An equation in the form $a x^{2}+b x+c=0,$ where $a, b,$ and $c$ are real numbers and $a \neq 0,$ is $\mathrm{a}(\mathrm{n})$ _________ equation, also called a(n) ________ degree equation. The greatest degree of the variable is _____.

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00:28

Problem 2

Which of the following are quadratic equations?
A. $x+2 y=0$
B. $x^{2}-8 x+16=0$
C. $2 x^{2}-5 x=3$
D. $x^{3}+x^{2}+4=0$

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00:23

Problem 3

Which quadratic equation is in standard form?
A. $x^{2}=25$
B. $3 x^{2}-x=4$
C. $(x-5)^{2}=16$
D. $x^{2}-x-2=0$

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00:42

Problem 4

The equation $x^{2}=-9$ has solutions that (are/are not) real numbers. These solutions involve the imaginary unit $i,$ which is defined as $i=$ ________ Thus, $i^{2}=$ ____________ For any positive real number $a$, we have $\sqrt{-a}=$ __________.

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01:25

Problem 5

Match each equation in Column I with the correct description of its solution in Column II.
I
(a) $x^{2}=12$
(b) $x^{2}=-16$
(c) $x^{2}=\frac{25}{36}$
(d) $x^{2}=100$
II
A. Two nonreal complex
B. Two integer solutions solutions
C. Two irrational solutions
D. Two rational solutions that are not integers

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00:51

Problem 6

A student incorrectly solved the following equation as shown.
$$
\begin{array}{r}
x^{2}-x-2=4 \\
(x-2)(x+1)=4 \\
x-2=4 \text { or } x+1=4 \\
x=6 \quad \text { or } \quad x=3
\end{array}
$$
Solve correctly and give the solution set.

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00:37

Problem 7

A student solving $x^{2}=81$ wrote the solution set incorrectly as $\{9\} .$ Her teacher did not give her full credit. The student argued that because $9^{2}=81,$ her answer had to be correct. Give the correct solution set.

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00:41

Problem 8

When solving a quadratic equation, a student obtained the solutions $x=\frac{3+2 \sqrt{5}}{2}$ or $x=\frac{3-2 \sqrt{5}}{2}$ and he wrote the solution set incorrectly as $\{3 \pm \sqrt{5}\}$. Give the correct solution set.

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00:39

Problem 9

Solve using the zero-factor property.
$$
x^{2}-x-56=0
$$

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00:32

Problem 10

Solve using the zero-factor property.
$$
x^{2}-2 x-99=0
$$

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00:37

Problem 11

Solve using the zero-factor property.
$$
x^{2}-8 x+15=0
$$

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00:27

Problem 12

Solve using the zero-factor property.
$$
x^{2}-6 x+5=0
$$

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00:34

Problem 13

Solve using the zero-factor property.
$$
x^{2}=121
$$

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00:28

Problem 14

Solve using the zero-factor property.
$$
x^{2}=144
$$

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00:27

Problem 15

Solve using the zero-factor property.
$$
x^{2}-169=0
$$

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00:26

Problem 16

Solve using the zero-factor property.
$$
x^{2}-400=0
$$

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00:44

Problem 17

Solve using the zero-factor property.
$$
3 x^{2}-13 x=30
$$

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00:36

Problem 18

Solve using the zero-factor property.
$$
5 x^{2}-14 x=3
$$

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00:56

Problem 19

Solve using the zero-factor property.
$$
6 x^{2}+19 x+10=0
$$

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00:41

Problem 20

Solve using the zero-factor property.
$$
8 x^{2}+18 x+9=0
$$

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00:24

Problem 21

Solve using the square root property. Simplify all radicals.
$$
x^{2}=81
$$

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00:23

Problem 22

Solve using the square root property. Simplify all radicals.
$$
z^{2}=169
$$

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00:24

Problem 23

Solve using the square root property. Simplify all radicals.
$$
x^{2}=144
$$

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00:18

Problem 24

Solve using the square root property. Simplify all radicals.
$$
m^{2}=36
$$

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00:17

Problem 25

Solve using the square root property. Simplify all radicals.
$$
k^{2}=14
$$

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00:26

Problem 26

Solve using the square root property. Simplify all radicals.
$$
m^{2}=22
$$

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00:39

Problem 27

Solve using the square root property. Simplify all radicals.
$$
t^{2}=48
$$

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00:26

Problem 28

Solve using the square root property. Simplify all radicals.
$$
x^{2}=54
$$

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00:26

Problem 29

Solve using the square root property. Simplify all radicals.
$$
x^{2}=\frac{25}{4}
$$

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00:24

Problem 30

Solve using the square root property. Simplify all radicals.
$$
m^{2}=\frac{36}{121}
$$

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00:19

Problem 31

Solve using the square root property. Simplify all radicals.
$$
x^{2}=0.25
$$

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00:17

Problem 32

Solve using the square root property. Simplify all radicals.
$$
w^{2}=0.49
$$

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00:20

Problem 33

Solve using the square root property. Simplify all radicals.
$$
x^{2}-64=0
$$

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00:18

Problem 34

Solve using the square root property. Simplify all radicals.
$$
x^{2}-100=0
$$

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00:22

Problem 35

Solve using the square root property. Simplify all radicals.
$$
r^{2}-3=0
$$

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00:20

Problem 36

Solve using the square root property. Simplify all radicals.
$$
x^{2}-13=0
$$

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00:41

Problem 37

Solve using the square root property. Simplify all radicals.
$$
x^{2}-12=0
$$

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00:33

Problem 38

Solve using the square root property. Simplify all radicals.
$$
x^{2}-8=0
$$

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00:43

Problem 39

Solve using the square root property. Simplify all radicals.
$$
4 x^{2}-72=0
$$

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00:40

Problem 40

Solve using the square root property. Simplify all radicals.
$$
2 x^{2}-80=0
$$

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00:33

Problem 41

Solve using the square root property. Simplify all radicals.
$$
2 t^{2}+7=61
$$

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00:38

Problem 42

Solve using the square root property. Simplify all radicals.
$$
3 x^{2}+8=80
$$

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00:49

Problem 43

Solve using the square root property. Simplify all radicals.
$$
3 x^{2}-8=64
$$

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00:35

Problem 44

Solve using the square root property. Simplify all radicals.
$$
2 x^{2}-5=35
$$

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00:34

Problem 45

Solve using the square root property. Simplify all radicals.
$$
7 x^{2}=4
$$

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00:29

Problem 46

Solve using the square root property. Simplify all radicals.
$$
2 x^{2}=9
$$

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00:30

Problem 47

Solve using the square root property. Simplify all radicals.
$$
5 x^{2}+4=8
$$

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00:41

Problem 48

Solve using the square root property. Simplify all radicals.
$$
7 p^{2}-5=11
$$

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00:42

Problem 49

Solve using the square root property. Simplify all radicals.
$$
(x-3)^{2}=25
$$

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00:32

Problem 50

Solve using the square root property. Simplify all radicals.
$$
(x-7)^{2}=16
$$

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00:32

Problem 51

Solve using the square root property. Simplify all radicals.
$$
(x-4)^{2}=3
$$

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00:26

Problem 52

Solve using the square root property. Simplify all radicals.
$$
(x+3)^{2}=11
$$

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00:52

Problem 53

Solve using the square root property. Simplify all radicals.
$$
(x-8)^{2}=27
$$

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00:39

Problem 54

Solve using the square root property. Simplify all radicals.
$$
(p-5)^{2}=40
$$

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01:07

Problem 55

Solve using the square root property. Simplify all radicals.
$$
(3 x+2)^{2}=49
$$

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00:58

Problem 56

Solve using the square root property. Simplify all radicals.
$$
(5 t+3)^{2}=36
$$

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00:44

Problem 57

Solve using the square root property. Simplify all radicals.
$$
(4 x-3)^{2}=9
$$

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00:32

Problem 58

Solve using the square root property. Simplify all radicals.
$$
(7 z-5)^{2}=25
$$

Nick Johnson
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00:45

Problem 59

Solve using the square root property. Simplify all radicals.
$$
(5-2 x)^{2}=30
$$

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00:34

Problem 60

Solve using the square root property. Simplify all radicals.
$$
(3-2 x)^{2}=70
$$

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01:07

Problem 61

Solve using the square root property. Simplify all radicals.
$$
(3 k+1)^{2}=18
$$

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00:49

Problem 62

Solve using the square root property. Simplify all radicals.
$$
(5 z+6)^{2}=75
$$

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00:50

Problem 63

Solve using the square root property. Simplify all radicals.
$$
\left(\frac{1}{2} x+5\right)^{2}=12
$$

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00:46

Problem 64

Solve using the square root property. Simplify all radicals.
$$
\left(\frac{1}{3} m+4\right)^{2}=27
$$

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00:43

Problem 65

Solve using the square root property. Simplify all radicals.
$$
\left(x-\frac{1}{8}\right)^{2}=\frac{1}{64}
$$

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00:34

Problem 66

Solve using the square root property. Simplify all radicals.
$$
\left(x-\frac{1}{9}\right)^{2}=\frac{1}{81}
$$

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00:43

Problem 67

Solve using the square root property. Simplify all radicals.
$$
\left(x-\frac{1}{3}\right)^{2}=\frac{4}{9}
$$

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00:30

Problem 68

Solve using the square root property. Simplify all radicals.
$$
\left(x-\frac{1}{5}\right)^{2}=\frac{16}{25}
$$

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00:43

Problem 69

Solve using the square root property. Simplify all radicals.
$$
\left(x+\frac{1}{4}\right)^{2}=\frac{3}{16}
$$

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00:44

Problem 70

Solve using the square root property. Simplify all radicals.
$$
\left(x+\frac{1}{7}\right)^{2}=\frac{11}{49}
$$

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00:52

Problem 71

Solve using the square root property. Simplify all radicals.
$$
(4 x-1)^{2}-48=0
$$

Nick Johnson
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00:49

Problem 72

Solve using the square root property. Simplify all radicals.
$$
(2 x-5)^{2}-180=0
$$

Nick Johnson
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00:37

Problem 73

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-100
$$

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00:21

Problem 74

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-64
$$

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00:32

Problem 75

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-26
$$

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00:23

Problem 76

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-21
$$

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00:27

Problem 77

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-12
$$

Nick Johnson
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00:31

Problem 78

Solve each equation. (All solutions are nonreal complex numbers.)
$$
x^{2}=-18
$$

Nick Johnson
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00:52

Problem 79

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(x+3)^{2}=-4
$$

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00:41

Problem 80

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(x-5)^{2}=-36
$$

Nick Johnson
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00:29

Problem 81

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(r-5)^{2}=-3
$$

Nick Johnson
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00:32

Problem 82

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(t+6)^{2}=-5
$$

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00:57

Problem 83

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(6 k-1)^{2}=-8
$$

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00:41

Problem 84

Solve each equation. (All solutions are nonreal complex numbers.)
$$
(4 m-7)^{2}=-27
$$

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01:02

Problem 85

Use Galileo's formula to solve each problem. Round answers to the nearest tenth.
The sculpture of American presidents at Mount Rushmore National Memorial is $500 \mathrm{ft}$ above the valley floor. How long would it take a rock dropped from the top of the sculpture to fall to the ground? (Data from www.travelsd.com)

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00:33

Problem 86

Use Galileo's formula to solve each problem. Round answers to the nearest tenth.
The Gateway Arch in St. Louis, Missouri, is $630 \mathrm{ft}$ tall. How long would it take an object dropped from the top of the arch to fall to the ground? (Data from www.gatewayarch.com)

Nick Johnson
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