Răspuns :
E(X)=(x+2)^2-9/x^2-25 : x-1/x-5
(x+2)^2-9=(x+2-3)(x+2+3)=(x-1)(x+5)
x^2-25=(x-5)(x+5)
E(x)=(x-1)(x+5)/(x-5)(x+5) x (x-5/x-1)
(se simplifica x-1 cu x -1 , x+5 cu x+5 si x-5 cu x-5)
E(x)=1
E(X)=(x+2)^2-9/x^2-25 : x-1/x-5
(x+2)^2-9=(x+2-3)(x+2+3)=(x-1)(x+5)
x^2-25=(x-5)(x+5)
E(x)=(x-1)(x+5)/(x-5)(x+5) x (x-5/x-1)
(se simplifica x-1 cu x -1 , x+5 cu x+5 si x-5 cu x-5)
E(x)=1