A^2-10a+25/a+4 : a-5/a^2-16

Question

A^2-10a+25/a+4 : a-5/a^2-16

Answer 1

(a²-10a+25)/(a+4) : (a-5)/(a²-16) = (a-5)²/(a+4) : (a-5)/((a-4)(a+4)) = (a-5)²/(a+4) * ((a-4)(a+4))/(a-5) = (a-5)*(a-4)