# Math Help - Multiplying Rational Expressions

1. ## Multiplying Rational Expressions

3x+6
_______ *
X^2-4

x^2-2x
________
9

*the x^2 cancel our right?
*do I factor 3x + 6 into 3(x+2)?
Can someonw please walk me through this?

2. Originally Posted by spikeymikey
3x+6
_______ *
X^2-4

x^2-2x
________
9

*the x^2 cancel our right?
*do I factor 3x + 6 into 3(x+2)?
Can someonw please walk me through this?
We need to factor before we reduce

$\frac{3x+6}{x^2-4} \cdot \frac{x^2-2x}{9} \iff \frac{3(x+2)}{(x-2)(x+2)} \cdot \frac{x(x-2)}{9}$

reducing the above we get

$\frac{3(x+2)}{(x-2)(x+2)} \cdot \frac{x(x-2)}{9}=\frac{x}{3}$

3. ## Ok

Originally Posted by spikeymikey
3x+6
_______ *
X^2-4

x^2-2x
________
9

*the x^2 cancel our right?
*do I factor 3x + 6 into 3(x+2)?
Can someonw please walk me through this?
IF the first problem is supposed to be $\frac{3x+6}{x^2-4}$...then you do the following...factor top and bottom to get $\frac{3(x+2)}{(x+2)(x-2)}$...cancel the $x+2$ to get $\frac{3}{x-2}$

4. Originally Posted by TheEmptySet
We need to factor before we reduce

$\frac{3x+6}{x^2-4} \cdot \frac{x^2-2x}{9} \iff \frac{3(x+2)}{(x-2)(x+2)} \cdot \frac{x(x-2)}{9}$

reducing the above we get

$\frac{3(x+2)}{(x-2)(x+2)} \cdot \frac{x(x-2)}{9}=\frac{x}{3}$
Thank you

5. So for....
x^2+6x+5 over 3x^2+3x Mutiplied by x^2-x-20 over x^2-25

I got a final result of 1 over 3x.....is that correct?

6. ## sorry :(

Originally Posted by spikeymikey
So for....
x^2+6x+5 over 3x^2+3x Mutiplied by x^2-x-20 over x^2-25

I got a final result of 1 over 3x.....is that correct?
$\frac{x^2+6x+5}{3x^2+3x} \cdot \frac{x^2-x-20}{x^2-25} \iff \frac{(x+1)(x+5)}{3x(x+1)} \cdot \frac{(x-5)(x+4)}{(x-5)(x+5)}= \frac{(x+4)}{3x}$

7. Originally Posted by TheEmptySet
$\frac{x^2+6x+5}{3x^2+3x} \cdot \frac{x^2-x-20}{x^2-25} \iff \frac{(x+1)(x+5)}{3x(x+1)} \cdot \frac{(x-5)(x+4)}{(x-5)(x+5)}= \frac{(x+4)}{3x}$
ok I see where I made the mistake

8. I need help with one more....

7x^3*y^4 over 6xy DIVIDED by 14x^2*y^2 over 36x^2y

9. Originally Posted by spikeymikey
I need help with one more....

7x^3*y^4 over 6xy DIVIDED by 14x^2*y^2 over 36x^2y
Do yourself and do us a favor and start a new thread if you have a new problem to solve.