Question

What is the y-value of the vertex of 4x2 + 8x - 8?

Answer 1

The answer would be -12

Answer 2

-12

Explanation:

To put the equation into vertex form, you can factor out the leading coefficient, then add and subtract a value equal to the square of half the x-coefficient (inside parentheses).

= 4(x^2 +2x) -8

= 4(x^2 +2x +1) -8 -4

= 4(x +1)^2 -12

The y-value of the vertex is -12.