Question

What is the axis of symmetry for f(x) = 2x2 − 8x 8? x = −2 x = −3 x = 3 x = 2

Answer 1

The first part of the quadratic formula, x = - b/2a, is the equation of the axis of symmetry, and the x-coordinate of the vertex. 

In standard form: - 2x² + 8x - 5 = 0, a = - 2, b = 8, c = - 5 

The axis of symmetry: x = - 8/2(- 2) = - 8/- 4 = 2 

Go back and solve for y to find the y-coordinate of the vertex. 

y = - 2(2)² + 8(2) - 5 

y = - 2(4) + 16 - 5 

y = - 8 + 16 - 5 

y = 3 

Vertex is (2, 3)

Answer 2

The answer i got was x=2