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

Feb 28, 2016

${x}_{\text{vertex}} = - 3.75$

I will let you work out ${y}_{\text{vertex}}$

#### Explanation:

Given:$\text{ } y = 2 {x}^{2} + 15 x - 2$

A quick way of finding ${x}_{\text{vertex}}$ is as follows:

Write as $\text{ } y = 2 \left({x}^{2} + \frac{15}{2} x\right) - 2$

Now apply :$\text{ } \left(- \frac{1}{2}\right) \times \frac{15}{2} = - \frac{15}{4} = 3.75$

$\textcolor{b l u e}{{x}_{\text{vertex}} = - 3.75}$
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Now substitute back into the original equation to find ${y}_{\text{vertex}}$