# Thread: common denominator with variables

1. ## common denominator with variables

I am good at mathematics. However, since I stop studying pure math for about a year now, I am having trouble with a simple process to solve fraction questions. How do you get a common denominator in the following equation

((4x/5xy)(15y/16x^2))

The answer is 3/4x^2 however, I cannot remember the steps needed to solve this question. It is starting to annoy me.

2. No common denominator is needed with multiplication of fractions. Just times across and cancel terms where you can.

3. Originally Posted by pickslides
No common denominator is needed with multiplication of fractions. Just times across and cancel terms where you can.

4. Originally Posted by Barthayn
((4x/5xy)(15y/16x^2))
Do the multiplying:
60xy / (80x^3 y)
Simplify:
3 / (4x^2)

5. Originally Posted by Barthayn
In this case, you should multiply the numerator and denominator of each fraction by the denominator of the other fraction and then add or subtract. So your common denominator is the product of the two denominators.

6. Originally Posted by Manfriedthetalkingpinata
So your common denominator is the product of the two denominators.
As PickS said, there is NO common denominator involved...same as (1/2) * (1/4) = 1/8