Question

Write x2 - 12x + 8 in vertex form. a. (x-6)2 -28 = 0 b. (x-4)2 - 11 = 0 c. (x-4)2 - 13 d. (x-4)2 - 15

Answer 1

y = x² - 12x + 8

First step is to move the 8 to the other side by subtract 8 from both sides. This gives you:

y - 8 = x² - 12x

Now we complete the square. Divide the b term (in this case 12) by 2, then square the result. You will then add that square to both sides. This gives you:

y - 8 + 36 = x² - 12x + 36

Combine like terms and factor:

y + 28 = (x - 6)²

y = (x - 6)² - 28. Option A should be your answer.