Question

7ab/a^2-b^2 - a-b/a+b subtract and simplify by removing a factor of 1 if possible

Answer 1

first you can notice that a^2-b^2=(a+b)(a-b)
so we have to multiply by (a-b) the second part to get the same denominator
\[7ab /(a^2-b^2)- (a-b)^2/(a^2-b^2)\]
\[(9ab-a^2-b^2)/(a^2-b^2)\]