Don't know what to do and need your help!

If Y1 and Y2 are random variables of the discrete type having the probability distribution

f(y1,y2) = (y1 + 2y2)/18, (y1,y2) = {(1,1),(1,2),(2,1),(2,2)}

(a) Find E(Y1 + 2Y2) and V(Y1 + 2Y2).

Hint: Make a joint probability distribution table.

E(Y1 + 2Y2) = E(Y1) + 2E(Y2) and V(Y1+2Y2) = V(Y1)+4V(Y2)+4Cov(Y1,Y2).

(b) Find the conditional mean and variance of Y2, given Y1 = 2.