# What is the vertex form of y=(x+4)(2x-1)?

Apr 28, 2017

$y = 2 {\left(x + \frac{7}{4}\right)}^{2} - \frac{81}{8}$

#### Explanation:

First you need to expan this function
$y = 2 {x}^{2} + 7 x - 4$
And I need to transform this function into this type like
$y = a {\left(x - h\right)}^{2} + k$
So
$y = 2 \left({x}^{2} + \frac{7}{2} x\right) - 4$
$y = 2 \left({x}^{2} + \frac{7}{2} x + \frac{49}{16}\right) - 4 - \frac{49}{8}$
Final
$y = 2 {\left(x + \frac{7}{4}\right)}^{2} - \frac{81}{8}$