Question

What is the vertex of `y=-2x^2+8x-12`?

Answer 1

`x_("vertex")=2` ...I will let you find y by substitution

Explanation:

This is a real cool trick

Given: `y=-2x^2+8x-12`

Write as `y=-2(x^2-8/2x)-12`

Consider the `-8/2 " from " -8/2x`

Apply this process: `(-1/2)xx(-8/2) = + 8/4=2`

`x_("vertex")=2`

You can see that this is true from the graph

Now all you have to do is substitute for x in the original equation to find y.