You can put this solution on YOUR website! Hello,
When subtracting fractions common denominators are needed.
In this (7)/(y^2-49)-(6)/(y^2-2y-35) we can factor the denominators to be:
(7)/[(y-7)(y+7)]-(6)/[(y-7)(y+5)]
So multiply the first fraction by (y+5)/(y+5) and the second fraction by (y+7)
to get:
7(y+5)/[(y-7)(y+7)(y+5)]-6(y+7)/[(y+5)(y-7)(y+7)]
Notice we now have the same denominators and this can be written as:
7(y+5)-6(y+7)/[(y+5)(y-7)(y+7)]
Expand the numerator out to get:
7y+35-6y-42/[(y+5)(y-7)(y+7)]
Combine like terms to get:
(y-7)/[(y+5)(y-7)(y+7)]
(y-7) cancels out to give us:
1/[(y+5)(y+7)]
Make sense?
RJ
www.math-unlock.com
