let A,B,C be sets, and let f : A--> B and g : B--> C be functions. The composite function denoted by g o f is a function from A to C defined as follows:
g o f(x)=g(f(x)) for every x in A.
Prove that if g o f is one-to one, then f is one-to one
Prove that is g o f is onto, then g is onto
The Attempt at a Solution
I really don't know how to approach this problem. I didnt things similar with binary structures determining if they are an isomorphism by not familiar with composite functions