# How do you identify the important parts of y= ½(x-4)(x+2) to graph it?

Oct 5, 2015

Graph $y = \left(\frac{1}{2}\right) \left(x - 4\right) \left(x + 2\right)$

#### Explanation:

The important parts are:
a. x-coordinate of axes of symmetry and vertex:
$x = \frac{x 1 + x 2}{2} = \frac{4 - 2}{2} = 1$
y-coordinate of vertex: $y = \left(f 1\right) = \left(\frac{1}{2}\right) \left(- 3\right) \left(3\right) = - \frac{9}{2}$
b. y-intercept --> Make x = 0 --> $y = - \frac{8}{2} = - 4$
c. x-intercepts --> x = 4 and x = -2
graph{1/2(x - 4)(x + 2) [-10, 10, -5, 5]}