What Is a Quadratic Equation? Quiz

Which of these is a quadratic equation?

A

x^3 + x = x^3 - 4

B

(x - 3)(x + 3) = x^2 + 2x

C

(x + 2)^2 = 3x + 10

D

2x + 5 = 0

Is

(x - 3)(x + 3) = x^2 + 2x

a quadratic equation?

A No; it simplifies to

2x + 9 = 0

B No, because it has no constant term

C Yes; it simplifies to

x^2 - 2x - 9 = 0

D Yes, because it contains

x^2

A rectangle's length is

3

m more than its width

x

, and its area is

70

m². Which equation fits?

A

x^2 + 3x - 70 = 0

B

2x + 3 = 70

C

x^2 - 3x - 70 = 0

D

x^2 + 3x + 70 = 0

The product of two consecutive positive integers is

156

. With the smaller one

x

, which equation is correct?

A

x^2 + x - 156 = 0

B

x^2 + 1 = 156

C

x^2 - x - 156 = 0

D

2x + 1 = 156

Is

x = 3

a root of

2x^2 - 5x - 3 = 0

?

A No, since the value is

6

B Yes, since

18 - 15 - 3 = 0

C No, since the value is

-6

D Yes, since

2 \times 3 = 6

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