1. Simplify the expression ((5x^-2)/(4x^2))^-2

2. (x)/(x^2-81)-(9)/(81-x^2) =

For the first one the answer was 16x^8/25 but I don't know how to get that. For the second one the answer is 1/x-9 and I also don't know how to get that one.

Amy , you should check if your previous same post has been answered before posting it again

http://www.jiskha.com/display.cgi?id=1295837377