Question

Write x^2-12x+8 in vertex form.

Answer 1

The vertex form: y = a(x - h)² + k

y = ax² + bx + c then h = -b/2a and k = f(h).

y = x² - 12x + 8

a = 1; b = -12; c = 8

h = -(-12)/(2·1) = 12/2 = 6

k = f(6) = 6² - 12·6 + 8 = 36 - 72 + 8 = -28

Answer: y = (x - 6)² - 28.