Thread: Simplifying Rational Powers

Bah, okay.

I'm trying to find a common denominator right now for this part of the problem:



Don't I multiply the denominators together? Thus making it?




Now since I can subtract the numerators it means I get 9.

That ends up as the right answer for the exponent of this:

However, in the solution it baffles me because they got the following:



= 12x^8/6-5/6/y^4/3

It looks like they just multiplied it by two, but I didn't think that was how you got a common denominator...

Originally Posted by A Beautiful Mind

Bah, okay.

I'm trying to find a common denominator right now for this part of the problem:



Don't I multiply the denominators together? Thus making it?




Now since I can subtract the numerators it means I get 9.

That ends up as the right answer for the exponent of this:

However, in the solution it baffles me because they got the following:



= 12x^8/6-5/6/y^4/3

It looks like they just multiplied it by two, but I didn't think that was how you got a common denominator...

Think what the lowest common denominator of 3 and 6 is (it's not 18, nor 12)

Originally Posted by A Beautiful Mind

Bah, okay.

I'm trying to find a common denominator right now for this part of the problem:



Don't I multiply the denominators together? Thus making it?

No. If the two denominators are relatively prime, then yes, you would multiply the denominators together. But here, one number is a multiple of another. In that case, the common denominator would simply be the bigger number.

I'm aware of two methods to finding LCD's. This site explains both: How To Find The Least Common Denominator (LCD) .


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