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
- the axis of symmetry is -9
for now I'm just gonna type my work and figure out what to do next
- fubd the line of symetrym -(b/2a)=x
- a = 1, b = -2, c = -8
- use this to find vertex
- 1^2 + -2 * 1 - 8= 1- 2 - 8 = -9 = y
- the vertex is x, -9
- find the axis of symetry
- the axis of symmetry is -9
- so so