Can i get some help these are the last 5 problems that im stuck with. -_-

(COMPLETED)1) (X-Y)^3 +27

(COMPLETED)2) X^2-A^2+X-A

(COMPLETED)3) 3x^(-3/2) - 12x^(1/2)

4) x^(1/2) (x-4)^(-1/2) +3x^(-1/2) (x-4)^(-3/2)

(COMPLETED)5) x^(2n+2) +x^(n+2)-56x^2

for 3 im think its (3x^-3/2)(1-4x^2) but yeah im not sure. but everything else im clueless at right now. thxs for hte help!