Understanding Subset Relations in Set Theory

[bernvall]

Homework Statement

if A is a subset of B, then B^c \ C is a subset of A^c \ C for any set C

Homework Equations

A is a subset of B = for all elements in A are also elements in B

A\B = the complement of a set B in a set A
A\B= A and B^c

The Attempt at a Solution

I tried opening it up but i still couldn't find a solution

 

[micromass]

Try to prove the contraposition: if x is not an element of $A^c\setminus C$, then x is not an element of $B^c\setminus C$.