1. The problem statement, all variables and given/known data Prove: The sum of r=0 to n [((-1)^r) * (nCr)] = 0. Prove: The sum of r=0 to n [nCr] = 2^n 2. Relevant equations It says to consider (1-1)^n and (1+1)^n , but I have no idea what this is even relating to honestly. 3. The attempt at a solution I need help getting started.