# What is the vertex form of  y= (x-4)(2x+2)-x^2+2x?

Jan 6, 2016

$y = {\left(x - \frac{7}{2}\right)}^{2} - \frac{111}{4}$

#### Explanation:

First simplify by multiplying out and grouping like terms together to get standard form.
$y = \left(2 {x}^{2} - 8 x + 2 x - 8\right) - {x}^{2} + 2 x$
$y = {x}^{2} - 7 x - 8$
Then the vertex form is
$y = {\left(x - \frac{7}{2}\right)}^{2} - \frac{79}{4} - 8$
$y = {\left(x - \frac{7}{2}\right)}^{2} - \frac{111}{4}$