Factoring Trinomials Using

FOIL Reversed

. . .also called guess and check

FACTORING POLYNOMIALS

GCF isfirst!

Are there any squared

terms left over?

2 Terms It is possibly the difference of two squares (DOTS)

3 TermsIf a = 1, do guess and check. If a is a number other than 1, do guess/check or factor by grouping (product/sum).

4 Terms Factor by grouping.

We’ll look into this

one today.

2 8 15y y FACTOR:

FACTORING is likeplaying JEOPARDY. Youhave the answer and must get the question.

2 8 15y y FACTOR:

2 8 15y y FACTOR:

( )( )

(y )(y )

2 8 15y y FACTOR:

(y )(y )

(y 5)(y 3)

2 8 15y y (y 5)(y 3)

Wait until later to decide what signs go there.

2 8 15y y (y 5)(y 3)

15 could be5 times 3

Or-5 times -3

2 8 15y y

( 5)( 3)y y Try:

3y

5y

2 8 15y y

3y 5yand

don’t make –8y.

2 8 15y y

PLUS

HAS TO ADD UP TO THE MIDDLE TERM.

2 8 15y y

( 5)( 3)y y Try:

3y

5y

2 8 15y y ( 5)( 3)y y

There is a lot more to factoring.It takes lots of practice.

THEEND