What is the the vertex of $y = (x -3)^2+8x-15$ ?

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Answer 1 · 2017-12-29T12:11:46

The vertex is $(-1,-7)$ .

First expand and collect like terms:

$y=x^2-6x+9+8x-15$
$y=x^2 + 2x -6$

Now the vertex is $(h,k)$ , where $h=-b/(2a)$ and $k$ is the value of $y$ when $h$ is substituted into the function.

$h=-2/(2*1)=-1$

$k = (-1)^2 +2(-1) -6 = 1-2-6=-7$

The vertex is $(-1,-7)$ .

What is the the vertex of y = (x -3)^2+8x-15 y = (x -3)^2+8x-15 ?