# How do you find the vertex of y= -x^2+18x-75?

Nov 25, 2015

Find vertex of y = -x^2 + 18x - 75

Ans: Vertex (9, 6)

#### Explanation:

x-coordinate of vertex:
$x = \left(- \frac{b}{2 a}\right) = \left(- \frac{18}{-} 2\right) = 9$
y-coordinate of vertex:
y = y(9) = - 81 + 162 - 75 = 6.