I'm studying binomial theorem in my Data Management class and I'm having trouble with the following questions ... hopefully someone here can help?

1) Use the binomial theorem to find the value of (1.05)^10 correct to 3 decimal places

2) The first three terms in the expression of (1 + ay)^n are 1, 12y, and 68y^2. Find a and n.

3) Prove: C(n, 0) - C(n, 1) + C(n, 2) - C(n, 3) ... = 0

Where C(n, r) is the choose function.