1. Graphing Quadratic Equations
CA 21.0, 23.0

2. Objective - To graph a quadratic equation

3. Write the answer as an ordered pair
Graphing Quadratics
Step 1: Find the axis of symmetry
Step 2: Find the vertex
Plug your answer from step 1 into the original equation and solve for y
Write the answer as an ordered pair
(x,y)
Step 3: Find the y-intercept
Identify c (0,c)

4. Graphing Quadratics
Step 4: Make a T-Chart that includes the vertex as the middle point and the y-intercept
Step 5: Plot the points on the graph x
y = f(x) = ax2+bx+c y

5. GRAPH : y = x2 – 4x – 5 a = 1, b = – 4, c = –5
The vertex: y = x2 – 4x – 5
y = (2)2 – 4(2) – 5
y = 4 – 8 – 5
y = – 9
(2, – 9)
c = –5 (0, –5)

6. T-Chart x
y = f(x) = x2 – 4x – 5 y –5 2
y = (2)2 – 4(2) – 5 –9

7. The Graph

8. GRAPH : y + 6x = x2 + 9 y = x2 – 6x + 9 a = 1, b = – 6, c = 9
The vertex: y = x2 – 6x + 9
y = (3)2 – 6(3) + 9
y = 9 –
y = 0
(3, 0)
c = 9 (0, 9)

9. T-Chart x
y = f(x) = x2 – 6x + 9 y 9 3
y = (3)2 – 6(3) + 9

10. The Graph