Evaluate each of the following expressions: (a) (sigma^x_k = 0 (5 k) 0.2^k 0.8^5-k for x = 0, 1, 2, and 3 (b) sigma^x_k = 0 2^k e^-2/k! for x = 0, 1, 2, and 3 Evaluate each of the following expressions: (a) (sigma^x_k = 0 (5 k) 0.2^k 0.8^5-k for x = 0, 1, 2, and 3 (b) sigma^x_k = 0 2^k e^-2/k! for x = 0, 1, 2, and 3