Answer:
f(x) = (x + 6)² - 29
Step-by-step explanation:
Given
f(x) = x² + 12x + 7
To complete the square
add/subtract ( half the coefficient of the x- term )² to x² + 12x
x² + 2(6)x + 36 - 36 + 7
= (x + 6)² - 29, thus
f(x) = (x + 6)² - 29
f(-9) means x is -9
Replace x with -9 and solve:
2/3(-9) - 6
Simplify:
-6 - 6 = -12
f(-9) = -12
Answer:
C) 75 + 50x = 25 + 70x
Step-by-step explanation:
ABC Tech:
$50 an hour. So,for x hours= 50 * x = 50x
Service charge = 75 + 50x
Tech Squad:
$70 an hour. So,for x hours= 70 * x = 70x
Service charge = 25 + 70x
C) 75 + 50x = 25 + 70x
50x - 70x = 25 - 75
-20x = -50
x = -50/-20
x =5/2 = 2
hours