## anonymous one year ago What is the common denominator of 1/a + 1/b in the complex fraction (1/a-1/b ) / (1/a+1/b) a^2 b^2 a – b a + b ab

1. freckles

so it asked to find a common denominator, not the least common denominator?

2. freckles

can i ask you how you would combine the following fractions: $\frac{1}{2}+\frac{1}{3}$

3. anonymous

wouldnt you just add them straight across

4. anonymous

oh shoot or is the where you cant add the denominators unless theyre the same

5. freckles

you have to have find a common denominator to add the fractions one such being 6 2 goes into 6, 3 times 3 goes into 6, 2 times you can multiply the fraction fraction by 3/3 and the second fraction by 2/2 notice a common denominator can be found just by multiplying 2 and 3. $\frac{1}{2}\frac{3}{3}+\frac{1}{3} \frac{2}{2} \\ \frac{3}{6}+\frac{2}{6} \text{ see we have found a common denominator } \\ \text{ now we can add } \\ \frac{3+2}{6}=\frac{5}{6} \\ \text{ so } \frac{1}{2}+\frac{1}{3}=\frac{5}{6}$

6. freckles

so what do you think the a common denominator of 1/a,1/b would be so that you could add 1/a+1/b?

7. freckles

remember I just found a common denominator above just by multiplying the bottoms

8. freckles

what is the denominator of 1/a? what is the denominator of 1/b?

9. anonymous

ab?

10. freckles

yes a common denominator could be ab a common denominator can also be any multiple of that if you that ab*ab which is a^2b^2 is also a common denominator since this is multiple choice and you have both of those options i would go with the least common denominator ab