1. (5x – 2)(x + 3) = 0 5x – 2 = 0 x + 3 = 0 x = -3 x = 2/5
Warm-up: Solve: 5x2 + 13x – 6 = 0
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) = 0
5x – 2 = 0
x + 3 = 0
x = -3
x = 2/5

2. Agenda
Warmup
Check Homework
Notes 7-4D
Assignment

3. Lesson 7.4D Learning Target:
Solving more polynomial equations with the X-box method.

4. -36 X 6 -6 (2x + 3)(2x – 3) = 0 4x2 6x -6x -9 x = -3/2, x = 3/2
EX 1: Solve 4x2 – 9 = 0
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) = 0
x = -3/2, x = 3/2

5. 81 X -9 -9 -18 (x – 9)(x – 9) = (x – 9)2 x2 -9x -9x 81
EX 2: Factor: x2 - 18x + 81
Perfect square trinomial
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. EX 2 cont. : now SOLVE x2 - 18x + 81=0

7. EX 3: Solve: 40x = 0
First factor out the GFC (4x2 – 9)= 0
Now use the X-box: 2x 3
a = 4 b = c = 9
a·c
4x2 6x
-36 2x X 6 -6
-6x -9 -3 b
10(2x + 3)(2x -3) = 0

8. 10(2x + 3)(2x -3) = 0
2x + 3 = 0
2x - 3 = 0
x = -3/2
x = 3/2

9. ARE YOU A MASTER????
Solve 25x2 = 4
Solve: 9x2 + 6x + 1 = 0

10. 25x2 – 4 = 0 X 10 -10 (5x + 2)(5x – 2) = 0 25x2 10x -100 -10x -4
Solve 25x2 = 4
25x2 – 4 = 0
a = b = c = -4 5x 2
a·c
25x2
10x
-100 5x X 10
-10
-10x -4 -2 b
(5x + 2)(5x – 2) = 0

11. (5x + 2)(5x – 2)=0
5x + 2 = x – 2 = 0
5x = x = 2
x = 2/5
x = -2/5

12. 9 X 3 3 6 (3x + 1)(3x + 1) = 0 9x2 3x 3x 1 Solve: 9x2 + 6x + 1 = 0 3x
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) = 0

13. cont.: Solve: 9x2 + 6x + 1 = 0
(3x + 1)(3x + 1) = 0
(3x + 1) = 0
x = -1/3