# What is the vertex form of y=2x^2 + 2x+6?

Dec 30, 2017

$y = 2 {\left(x + \frac{1}{2}\right)}^{2} + \frac{11}{2}$

#### Explanation:

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

$\textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{2}{2}} \textcolor{b l a c k}{y = a {\left(x - h\right)}^{2} + k} \textcolor{w h i t e}{\frac{2}{2}} |}}}$

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

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

• " the coefficient of the "x^2" term must be 1"

$\Rightarrow y = 2 \left({x}^{2} + x + 3\right)$

• " add/subtract "(1/2"coefficient of the x-term")^2" to"
${x}^{2} + x$

$y = 2 \left({x}^{2} + 2 \left(\frac{1}{2}\right) x \textcolor{red}{+ \frac{1}{4}} \textcolor{red}{- \frac{1}{4}} + 3\right)$

$\Rightarrow y = 2 {\left(x + \frac{1}{2}\right)}^{2} + \left(2 \times \frac{11}{4}\right)$

$\Rightarrow y = 2 {\left(x + \frac{1}{2}\right)}^{2} + \frac{11}{2} \leftarrow \textcolor{red}{\text{in vertex form}}$