honors algebra 1
posted by fredrich .
if f(x)=2x and g(f(x))=x, find g(x)

composition function
g(f(x))
so where ever you see x in the g(x) equation plug in f(x)
so do the reverse
g(x)= (1/2)x
so when you check your work
g(f(x))= (1/2(2x)) > the 1/2 and the 2 cancel and you are left with just x so it checks!