# What is the vertex form of y=(3x - 15)(x - 5) ?

Mar 7, 2016

$y = 3 {\left(x - 5\right)}^{2} + 0$

#### Explanation:

$y = a {\left(x - h\right)}^{2} + k$

and $\left(h , k\right)$ is the vertex of the parabola the equation represents.

Normally, to find the vertex form, we use a process called completing the square. In this case, however, we can simply factor our $3$ from the first factor and we are essentially done.

$\left(3 x - 15\right) \left(x - 5\right) = 3 \left(x - 5\right) \left(x - 5\right)$

$= 3 {\left(x - 5\right)}^{2} + 0$

Thus the vertex form is $y = 3 {\left(x - 5\right)}^{2} + 0$