1. Warm-up: Factor: 5x2 + 13x – 6
a = 5 b = c = -6 x 3
a·c
-30
5x2
15x 5x X 15 -2 13
-2x -6 -2 b
(5x – 2)(x + 3)

2. Warm up
Check homework…
Notes 7-3C more factoring of polynomials

3. Lesson 7.3C Learning Target:
Factor more polynomials using the X-box method.

4. EX 1: Factor 4x2 – x2 + 0x - 9
a = 4 b = c = -9
Use the X-box: 2x 3
a·c
4x2 6x
-36 2x X 6 -6
-6x -9 -3 b
(2x + 3)(2x – 3)

5. 81 X -9 -9 -18 (x – 9)(x – 9) = (x – 9)2 x2 -9x -9x 81
EX 2: Factor: x2 - 18x + 81
a = 1 b = c = 81
Use the X-box: x -9
a·c x2
-9x 81 x X -9 -9
-9x 81
-18 -9 b
(x – 9)(x – 9)
= (x – 9)2

6. 40x2 + 0x – 90 -36 X 6 -6 4x2 6x -6x -9 EX 3: Factor: 40x2 – 90 2x 3
Hmmm….a = 4 b = c = 9
10(4x2 + 0x – 9) 2x 3
Use the X-box:
a·c
4x2 6x
-36 2x X 6 -6
-6x -9 -3 b

7. ARE YOU A MASTER????
Factor 25x2 - 4
Factor: 9x2 + 6x + 1

8. Solve 25x2 - 4
25x2 – 4
a = b = c = -4 5x 2
a·c
25x2
10x
-100 5x X 10
-10
-10x -4 -2 b
(5x + 2)(5x – 2)

9. 9 X 3 3 6 (3x + 1)(3x + 1) 9x2 3x 3x 1 Factor: 9x2 + 6x + 1 3x 1 3x 1
a = 9 b = c = 1
Use the X-box: 3x 1
a·c
9x2 3x 9 3x X 3 3 3x 1 6 1 b
(3x + 1)(3x + 1)