Mutiplying Rational Equations

1. Apr 6, 2010

JerryClower

How do you multiply an equation that has 2 or more numerators. such as :

8x + 8 x - 1
______ X _______
X2 - 2x + 1 2x + 2

And don't say anything like, "I'm not doing your homework for you" or anything stupid like that. I just want to know how to do it, not the answer.

2. Apr 6, 2010

Staff: Mentor

$$\frac{A}{B} \times \frac{C}{D} = \frac{A \times C}{B \times D}$$

Does that help?

3. Apr 6, 2010

GreatEscapist

You must cross multiply, if I'm looking at this correctly.
So if A/B x C/D => A x D=B x C

So:
8x + 8 x - 1
______ X _______
X2 - 2x + 1 2x + 2
(Yeah, I just copied that. I'm assuming that B has an x2on the bottom)

(8x + 8)(2x+2)=(x2 - 2x)(x - 1)
Now combine like terms, and solve for x. You will probably have to factor.

4. Apr 6, 2010

Staff: Mentor

You're thinking of: if A/B = C/D, then A x D = B x C

This may or may not be what the OP meant.