Example 4 Graph f(x) = x^2 -2x - 8

Steps to Graph ax^2 + bx + c

• Find the vertex and the axis of symmetry. Sketch these in.
• Find the x-intercept by plugging in 0 for y.
• Find the y-intercept by plugging in 0 for x.
• Reflect your points across the axis of symmetry and connect your dots with a smooth U-shaped (not V-shaped) curve.
  

Graph f(x) = x^2 -2x - 8 

1. the axis of symmetry is -9

for now I'm just gonna type my work and figure out what to do next

1. fubd the line of symetrym -(b/2a)=x
2. a = 1, b = -2, c = -8
3. use this to find vertex
4. 1^2 + -2 * 1 - 8= 1- 2 - 8 = -9 = y
5. the vertex is x, -9
6. find the axis of symetry
7. the axis of symmetry is -9
8. so so To find the x-intercepts, you can set y equal to zero and solve for x:
9. x^2 - 2x - 8 = 0
   (x - 4)(x + 2) = 0
   x = 4 or x = -2