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

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Answer 1 · 2016-01-26T13:23:39

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

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.

enter image source here

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