I would make a great detective. I knew that Destini wouldn't let us down, so it didn't make sense that her posting wasn't up on the blog. What she did was create an entirely new blog site instead of creating a new post. So I've copied what she wrote yesterday and here it is.

Factoring Trinomials When a > 1.

Wednesday, September 20, 2006 ;

Today in class, we touched on the subject of factoring trinomials when a is greater than 1. This method was called The Grouping Method. There are 5 steps to complete this method.

Step One; Find the Factors of a * c.

Example: 15x

^{2}- 4x - 4

**15 would be concidered a & -4 would be concidered c .

**(15) (-4) = -60.

Find the factors of -60;

-60, 1 or 60, -1

-30, 2 or 30 , -2

-20, 3 or 20, -3

-15, 4 or -4 , 15

-12, 5 or -5 , 12

-10, 6 or -6 , 10

Step Two; Find the combination whose sum is equal to b. ( b = -4 )

It would be ( 6, -10 ) because -10 + 6 = -4.

Step Three; Break up the middle term using the factors from step two.

15x

^{2}-4x-4= 15x

^{2}-10x+6x-4

Step Four; Factor out a Greatest Common Factor (G.C.F.) from term 1,2 & 3,4.

15x

^{2}- 10 x + 6 x - 4= ( 5x ) ( 2 )= 5x(3x-2) + 2(3x-2)

Step Five; The 2 G.C.F.'s become the 1st factor and the brackets become the 2nd factor.

5x(3x-2) + 2(3x-2)= (5x+2) (3x-2)-

The assignment was Exersize #9. Questions 1 - 11 & 20. (omit questions 11-19)

P.S. - Xwan will be blogging next.. =)

posted by DestiniLyn