Math please help
posted by Amy .
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.