Jeez, where do people get these idiotic, tedious math problems. Also, try plugging this shit in Wolfram. Works more often than you'd think

no question actually asked but I will assume:
r=21, s=10, n=127

6)Simplify the expression
{1}/{x^2+4 x+4} - {1}/{x^2-3 x - 10}
and give your answer in the form of
\frac{f(x)}{g(x)}.

7)Simplify the expression
{2 x^2+3 x+1}/{x^2+2 x-3} (DIVISION) {x^2+5 x+4}/{2 x^2-3 x+1}
and give your answer in the form of
\frac{f(x)}{g(x)}.

did you try plugging into wolfram alpha? It's free, just google it. No downloads or anything. Just type the expression in the wolfram bar and search