Question

What is the vertex of the graph of the function f(x) = x2 + 8x - 2?

O (4.18)
O (0,-2)
O (-8,-2)
0 (4-18)

Answer 1

Option D, (-4,-18)

Explanation:

got it right on edge

Answer 2

Vertex is (-4, -18)

Explanation:

f(x) =
`ax^(2) +bx +c`

Let (h, k) be the vertex

An easy way to find h is to use the formula h = -b/2a

In your case where f(x) =
`x^(2) +8x - 2` a = 2 and b = 8

So, h = -8/2(1) = -8/2 = -4

Substitue -4 in for x to find k

k = (
`-4^(2)`) + 8(-4) - 2

= (16) - 32 - 2

= 16 - 32 - 2

= -18

Vertex is (-4, -18)

Note: Another way to find the vertex is to complete the square, but this can really be difficult in some cases