Question

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

Answer 1

Answer:

Vertex is (-4, -18)

Step-by-step 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