Help with this question (e),(f),(g)! I think c) answer is Cov(X,Y)=0

I will add several photos because some says they are seem to be broken, but they all all same pictures. Hope one of them works properly! Thank You!

6. The joint pdf fxy (a, b) is zero outside the triangular region shown below and is equal this joint pdf: to a fixed number y on the triangular region. Answer the following questions about (a) Calculate the value of y. (b) Are X and Y independent? Prove your answer and then intuitively explain why you think they are independent or dependent. (c) Calculate cov( X, Y). Does the result you obtain make sense? (d) Define Z = X2. Calculate the joint CDF Fzy (a, b) (e) Define Z - X2. Calculate cov( Z, Y). Compare this result with the result of part (c) and intuitively explain if both results make sense. (f) Calculate the CDF of X - Y. (g) Calculate the joint CDF of two random variables Z = X + Y and W = X - Y