Hello, can someone solve and explain this problem to me?

Let X1, X2, X3 be i.i.d. Binomial random variables with parameters n = 2 and p = 1/2. Define two new random variables Y1 = X1 - X3, Y2 = X2 - X3- We further introduce indicator random variables Z; E {0, 1} with Z; = 1 if and only if Y; = 0 for i = 1, 2. Calculate the covariance of Y1 and Y2. (Give an exact answer or a decimal accurate to at least 3 decimal places.) Cov (Y1, Y2) Calculate the variance of Z1. (Give an exact answer or a decimal accurate to at least 3 decimal places.) Var (Z1) = Calculate the covariance of Z1 and Z2. (Give an exact answer or a decimal accurate to at least 3 decimal places.) Cov (Z1, Z2) =