3-4 MORE Factoring!

Factoring by using the Greatest Common Factor

1. 2x2 + 8x - 6 =

2. 3x2 - 9x – 24 =

3. 8x2 – 40 =

4. 4x2 – 10x + 2 =

5. 6x2 - 6 =

6. 2x2 +8x – 24 =

Always check for a GCF first!!!!!! If you cannot factor out a GCF, then try this next method.

This method you are about to see is not mathematically sound --- it is a TRICK that works.

Slide and Divide

x²+11x+3( ) Slide the leading coefficient

x²+11x+18 Multiply

(x+9 )(x+2 ) Factor, then DIVIDE by leading coefficient

( x+3/ )( x+1/ ) Simplify fractions, then slide denominators in front of

x’s

6

2 3

/6 /6

6x2 – x – 2

Factor by using slide and divide.

Click here for answer

8x2 12x 4

If a GCF can be taken out first, you MUST take out the GCF before you “slide and divide.”

Click here for answer

Factor the expression. If the expression cannot be factored, say so.

1. 3x2 10x 8 (only 2 will not factor)2. 2x2 5x 33. 4x2 4x 1

4. 2x2 5x 1 Copy the problem into your notebook and

5. 4x2 5x 6 factor it.

6. 2x2 11x 15

7. 9x2 12x 4 *These are the problems from WB 4.4 (p. 62)

8. 12x2 24x 9 if you still have your workbook page

9. 18x2 2 from yesterday. If not, copy these

10.12x2 17x 6 down.

11.15x2 8x 16

12.4x2 513.12x2 39x 9

14.18x2 9x 14

15.20x2 54x 36

16.42x2 35x 7

17. 12x2 x 11

18.80x2 68x 12

Bellwork:

1. Factor: 4x2 - 25

2. Factor: 9x2 – 64

3. Solve x2 – 25x +100 = 0

Solve the equation.

4x2 5x 6 = 0

Solve the equation.

9x2 12x 3 = 0

• The area of the rectangle is 78cm. Find the length of each side.

x+2

3x + 1