# How do you find the vertex and intercepts for y = x^2-8x+7?

Feb 29, 2016

vertex (4, -9)

#### Explanation:

x-coordinate of vertex:
$x = - \frac{b}{2 a} = \frac{8}{2} = 4$
y-coordinate of vertex"
$y \left(4\right) = 16 - 32 + 7 = - 9$
y-intercept --> x = 0 --> y = 7
x-intercepts --> y = 0 --> solve ${x}^{2} - 8 x + 7 = 0.$
Since a + b + c = 0, use shortcut. --> x = 1 and $x = \frac{c}{a} = 7$
graph{x^2 - 8x + 7 [-20, 20, -10, 10]}