1. 8-6 Solving Quadratic Equations using Factoring
Goal:
Solve quadratic equation by factoring the trinomial.
Eligible Content: A

2. To solve equations by factoring:
Make sure equation ends with = zero.
Factor the trinomial.
Set each linear binomial equal to zero and solve for each variable.

3. Solve: x2 – 3x – 10 = 0 (x – 5)(x + 2) = 0 x – 5 = 0 x + 2 = 0 +5 +5
5 * 2 = 10
5 - 2 = 3
x = 5 or
x = -2

4. Examples x2 – 9x + 14 = 0 x2 + 15x + 50 = 0 x2 + 3x = 54 x2 + 51 = 20x
x = 2 or x = 7
x = -5 or x = -10
x = -9 or x = 6
x = 3 or x = 17
x = 8 or x = -1

5. Solve x2 – x – 20 = 0. Check your solution.
A. {–5, 4}
B. {5, 4}
C. {5, –4}
D. {–5, –4}

6. Practice
Worksheet – “8-6 Solving Quadratic Equations by Factoring”

7. Remember: The solutions are the x-intercepts of the graph.
We can check an answer by graphing it and finding x-intercepts.

8. Look at Graphs!
Let’s look at problems from worksheet again.

9. Homework
Page 507 #20-29