2. Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 – 3x – 12 = 0

A. 3.12, 3.77
B. –12.75, 15.75
C. 5.27, –2.27
D. 4.74, –1.74

C

Step-by-step explanation:

Given

x² - 3x - 12 = 0 ( add 12 to both sides )

x² - 3x = 12

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(- )x + = 12 +

(x - )² = ( take the square root of both sides )

x - = ± = ± ( add to both sides )

x = ±

Then

x = + ≈ 5.27 ( to the nearest hundredth )

x = - ≈ - 2.27 ( to the nearest hundredth )

step-by-step explanation:

first, eliminate the parenthesis:

3

x

+

2

−

4

x

second, group like terms:

3

x

−

4

x

+

2

third, combine like terms:

(

3

−

4

)

x

+

2

→

−

1

x

+

2

→

−

x

+

2

i would need to see the dot plot : )