# How do you write the Vertex form equation of the parabola #y=x^2 + 8x - 7#?

##### 1 Answer

#### Explanation:

Vertex form looks like this:

#y = a(x-h)^2+k#

Where

#y = (x-h)^2+k#

We need to complete the square.

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So we have

#y = x^2+8x-7#

Remember that to find

#c = b^2/(4a#

We can derive this from the quadratic formula, but that's a problem for another time. Anyway, in this case we have

#c = 8^2/(4(1)) = 64/4 = 16#

So what we need to do is add and subtract

#y = x^2+8x+16-7-16#

Notice that the first three terms are a perfect square.

#y = (x^2+2(4)x+4^2 )- 23#

#y = (x+4)^2-23#

This is the vertex form of our parabola.

*Final Answer*