Subract. Put the answer in the simplest form 9/x-4 - 5/x+4
I will assume you mean:
9/(x-4) - 5(x+4)
LCD is (x-4)(x+4)
= (9(x+4) - 5(x-4))/((x+4)(x-4)
= (9x + 36 - 5x + 20)/(x^2 - 16)
= (4x + 56)/(x^2 - 16)
9/(x-4) - 5(x+4)
LCD is (x-4)(x+4)
= (9(x+4) - 5(x-4))/((x+4)(x-4)
= (9x + 36 - 5x + 20)/(x^2 - 16)
= (4x + 56)/(x^2 - 16)