1. Algebra 2 10/11/16 EQ: How do I solve a quadratic by factoring
Algebra 2 10/11/16 EQ: How do I solve a quadratic by factoring? HW: pg 338 # 5-17 all, all Warm up: What are the roots of a quadratic and what is the equation of a parabola in x intercept(s) form?

2. Writing an equation in standard form
Recall y = a(x-p)(x-q) Write an equation with roots at -4 and 2. y = (x +4) (x-2) y = x2 +4x – 2x -8 y = x2 +2x -8 Question: What happened to a?
FOIL
Combine like terms

3. Your Turn
Recall y = a(x-p)(x-q) Write 2 equations with roots at 3 and -1.

4. Solve by Factoring ZERO
Recall that the y value of the roots is ________ .
Set equations to 0.
Factor any like terms (not needed but recommended)
Is a = 1 or something else?

5. a = 1
y = x2 + 9x + 18

6. a = 1
24 = x2 -2x

7. Factoring GCF
n2 + 5n = 0

8. y = 2x2 -10x +8

9. a ≠ 1
3x2 = -x + 4

10. 9x2 +12x +4

11. Word Problems
Find the dimensions of each side
A = 50 m2
X - 3
X + 2

12. Projectile
A ball is thrown upwards with an initial velocity of 64ft/s and an initial height of 10 ft.
Write an equation that describes the projectile
How long is it going to take for the ball to reach 72ft?
How many seconds will the ball be above 58ft?

13. Special Cases
Difference of squares (a2 – b2) = (a – b) (a + b) x2 – 25 = 9x2 – 36 = 100x2 – 1= x4 – 49 =

14. Special Cases (cont.)
Perfect Squares a2 + 2ab + b2 = (a + b)2 a2 - 2ab + b2 = (a - b)2 X2 + 6x + 9 = X2 + 10x + 25 = 4x2 – 24x + 36 = OR