f(x)=-x-3
g(x)=x+3
(fog)(x)= f(g(x))= f(x+3)= -x+3-3= -x
(gof)(x)= g(f(x))=g(-x-3)=-x-3+3=- x
(fof)(x)= f(-x-3)=x+3-3=x
(gog)(x)= g(g(x))= g(x+3)= x+3+3=x+6
f(x)=x+4
g(x)=x/2+3
f(g(x))=f(x/2+3)=x/2+7
g(f(x))=g(x+4)=(x+4)/2 +3
f(f(x))=f(x+4)=x+8
g(g(x))=g(x/2+3)=(x/2+3)/2+3
O seara buna!
