Question

What is the vertex form of `y = -x^2 + 8x − 13`?

Answer 1

`y = - (x - 4)^2 + 3`

Explanation:

`y = - x^2 + 8x - 13`
x-coordinate of vertex:
`x = -b/(2a) = -8/-2 = 4`
y-coordinate of vertex:
`y(4) = - 16 + 32 - 13 = 3`
Vertex form:
`y = - (x - 4)^2 + 3`