hi, i'm totally lost. i understand that you need to find a lowest common denominator to subtract two fractions (rational expressions) with different denominators. but what if the denominators are "x-1" and "x". is x the common denominator? if so what happens to the "-1"? do you know of any live online help i can get with the following:
3/(x-1) - (1-2x)/x
i've looked through my notes and have no examples that quite match that i can follow to get through it. please help!
thanks,
Simone
Hi Simone,
You know that with numerical fractions you can always find a common denominator by multiplying the denominators. For example if you have
1/8 - 5/12
then 12
8 = 72 is a common
denominator, even though it is not the lowest common denominator.
The same is true for rational expressions, if you multiply the denominators you will have a common denominator. In your example a common denominator is
x(x - 1)
Penny