# How do you solve #x^2-2x-8=0# by graphing?

##### 1 Answer

We need to find the vertex, x-intercepts, and y-intercept to give us an idea of what the graph will look like.

#### Explanation:

Let's find the vertex first. We can find the x-coordinate by using

The y-coordinate can be found by plugging the x-value back into the equation:

**The vertex is #(1,9)#.** Next, let's find the x-intercepts, which are the zeroes of the equation. Let's factor the polynomial and find them:

**The x-intercepts are #(4,0)# and #(-2,0)#.** Finally, the y-intercept can be found by letting

**The y-intercept is #(0,-8)#.** You can plot the bolded points, which will be able to create a decent outline of the parabola, If you need them, you can plot other points on the graph, such as

graph{x^2-2x-8 [-9, 11, -10, 1]}