Saturday

December 20, 2014

December 20, 2014

Posted by **Gretchen** on Thursday, June 4, 2009 at 12:59am.

I need help trying to figure out how to factor each quantity or parentheses.

and then simplifying it.

- 8th Grade Algebra -
**MathMate**, Thursday, June 4, 2009 at 1:07amFor (b^2-10b+21), start with listing the factors that multiply to give 21.

1,21

3,7

7,3

21,1

As 21 is positive and -10b is negative, you will find that the factors are in the following form:

(b-x)(b-y)

where x and y are chosen from the pair of factors. If you multiply out the factors, you will get

(b-x)(b-y)=b^2-(x+y)b+xy

Thus, you will choose from the list of factors a pair which will give

xy=21 and x+y=10.

Try the same for the denominator. It has more factors, so the list of factors will look like:

1,28

2,14

4,7

7,4

14,2

28,1

The method to follow is exactly the same as the numerator.

Tell us what you found.

**Answer this Question**

**Related Questions**

Simplifying Rational Expressions - 1) d + 7/d^2 - 49 2)b^2 - 10b + 21/b^2 - 11b...

7th gade math Ms. Sue please - 1. y minus five over three= 1 (1 point) –2 8 18 6...

Algebra - Solve 11b+6-2b+b=4b+5-3b-3-b for b. 10b+6= 2 ___-6_-6 10b=-4 Book says...

8th Grade Algebra...HELP! - Where do I add parentheses to make this expression ...

honors algebra II - factoring:: i factored 15A^2B - 10AB^2 into... (15A - 10B)(...

Algebra - Hi! Today I was absent from my algebra class, and they learned how to ...

Algebra II - I'm trying to factor this and I just can't figure it out. Help? r^4...

earth - If the Earth has so much mass, then how does it "float"? (My 8th grade ...

Math Algebra - I am stuck on simplifying four problems, I cannot figure out ...

Math 209 - When simplifying a rational fraction, why do you need to factor the ...