# What is the vertex of y= 2x^2 - 18x -6?

Mar 2, 2016

${x}_{\text{vertex}} = + \frac{9}{2}$
I will let you work out ${y}_{\text{vertex}}$ by substitution

#### Explanation:

Write as:$\text{ } y = 2 \left({x}^{2} - \frac{18}{2} x\right) - 6$

Apply $\text{ } \left(- \frac{1}{2}\right) \times \left(- \frac{18}{2}\right) = + \frac{9}{2}$

${x}_{\text{vertex}} = + \frac{9}{2}$
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To derive ${y}_{\text{vertex}}$ substitute $x = \frac{9}{2}$ into the original equation and solve for y