5/x^2+5x+x+15/25_-x^2
x^2+5x=x*(x+5)
25-x^2=(5-x)*(5+x)
(5/(x^2+5x)) +(x+15)/(25-x^2)=
=5*(5-x)/(x*(x+5)*(5-x)) + x*(x+15)/(x*(x+5)*(5-x)) =
=(5*(5-x) + x*(x+15))/(x*(x+5)*(5-x)) =
=(25 -5x +x^2+15x)/(x*(x+5)*(5-x)) =
=(x^2+10x+25)/(x*(x+5)*(5-x)) =
=(x+5)^2/(x*(x+5)*(5-x)) =
=(x+5)/(x*(5-x))