Updated May 13, 2011
f(x)=x^2-x
All real numbers
f(x)=x^2-1 and g(x)=x+2
y=4x-1
f(x)=1/2x+2, g(x)=2x-4
f(g(x))
f(x+2)=(x-2)^2-1
f(g(x))= x^2-4-1
f(g(x))= x^2-5