# What is the vertex form of y=(3x - 2) (4x + 1) ?

Aug 11, 2018

$y = 12 {\left(x - .208\right)}^{2} - 2.52$

#### Explanation:

First put the function into standard form by foiling:

$y = 12 {x}^{2} - 5 x - 2$

Find the vertex: $x = - \frac{b}{2 a}$

$x = \frac{5}{24}$ = $.208$

plug that into the original equation:

$\frac{300}{576} - \frac{25}{24} - 2$ = $- 2.52$

vertex$\left(h , k\right)$: ($.208$,$- 2.52$)

put it into $y = a {\left(x - h\right)}^{2} + k$ form:

$y = 12 {\left(x - .208\right)}^{2} - 2.52$
graph{y=12(x-.208)^2-2.52 [-10, 10, -5, 5]}