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

`(*)\qquad(a-b)^2=a^2-2ab+b^2`

`x^2-12x+8=x^2-2\cdot x\cdot6+8=\underbrace{x^2-2\cdot x\cdot6+6^2}_((*))-6^2+8\\\\=(x-6)^2-28\to\boxed{a.}`