# What is the vertex form of y= x^2 -2x - 15?

Jul 5, 2018

$y = {\left(x - 1\right)}^{2} - 16$

#### Explanation:

$\text{the equation of a parabola in "color(blue)"vertex form}$ is.

•color(white)(x)y=a(x-h)^2+k

$\text{where "(h,k)" are the coordinates of the vertex and a}$
$\text{is a multiplier}$

$\text{to obtain this form "color(blue)"complete the square}$

$y = {x}^{2} + 2 \left(- 1\right) x \textcolor{red}{+ 1} \textcolor{red}{- 1} - 15$

$y = {\left(x - 1\right)}^{2} - 16 \leftarrow \textcolor{red}{\text{in vertex form}}$