What is the y-value if the vertex of 4x^2 + 8x - 8

The x-value is -b/(2a) = -8/(2·4) = -1.

The corresponding y-value is ...

... 4(-1)² +8(-1) -8 = 4 -8 -8 = -12

The y-value of the vertex is -12.

The y-value of the vertex is

Step-by-step explanation:

we know that

The equation of a vertical parabola into vertex form is equal to

where

(h,k) is the vertex of the parabola

In this problem we have

-----> this a vertical parabola open upward

Convert to vertex form

Group terms that contain the same variable, and move the constant to the opposite side of the equation

Factor the leading coefficient

Complete the square. Remember to balance the equation by adding the same constants to each side

Rewrite as perfect squares

The vertex is the point

The y-value of the vertex is

the weight of the object inside the box!