Warmup

Factor.

1.

2.

3.

4

64 40ab

3 2 335 105m n m n

10 25 14 35xy x y

2 2 318 21 30 35x y x y y x

8(8 5 )ab

2 235 ( 3 )m n m n

(5 7)(2 5)x y

2(3 5)(6 7 )x y y x

10-3 Factoring Trinomials

Objective: To factor quadratic trinomials.

Standard 11.0

Remember…

(x+2)(x+5)

We used the box method to simplify this.

Today, we are going to work BACKWARDS!

New method…. The X BOX!!

2 7 10x x

Example 1

x2 + 14x + 45

45

14

9 5x2

45

9x

5x

x

x 9

5

(x + 9)(x + 5)

1st•3rd

2nd

Pick 2 #s that multiply to get the top and add to get the bottom.

Those go on the sides of the X.

Try w/ a partner

2 2 63x x

2 9 20a a

( 7)( 9)x x

( 4)( 5)a a

Example 2

3x2 + 10x + 8

24

10

6 43x2

8

6x

4x

3x

x 2

4

(x + 2)(3x + 4)

1st•3rd

2nd

Example 3

6y2 – 13y – 5

-30

-13

-15 26y2

-5

-15y

2y

3y

2y -5

1

(2y – 5)(3y + 1)

1st•3rd

2nd

TOO

220 21 5x x

212 11 5a a

(5 1)(4 5)x x

(4 5)(3 1)a a

Example 3

2 6 12x x PRIME

Helpful X hints…

+

+

+ +

+

-

- -

-

+

+ big - small

-

-

- big + small

Homework

Pg. 579 # 28-30, 32-35, 37

Math Lab Warmup

Factor.

1.

2.

3.

4

5 2 350 5xy x y

8 2 318 3mn m n

2 236 9x y

218 100x y x

Prime Factorization

70 215

1525

Find the GCF

42,63 24,40

3 2 4 4 5210 ;112x y z x y z

Grouping

Factor by grouping:

3 225 5 30 6x x x 3 24 12 5 15y y y

Try with a mathleteFactor by grouping:

3 224 64 21 56x x x

9 4 3 12ab cd ad cb

Factoring Trinomials

2 6 5x x 2 7 12x x

Factoring Trinomials

22 5 3x x 23 5 2x x