X1 and X2 are two independent discrete random variables with
P(X1 = k) = c3-k
P(X2 = k) = d4-k
for k in natural numbers and where X1, X2 in natural numbers is almost always valid. 0 is not include in N.
Find constants c and d.
The Attempt at a Solution
Since I'm joining this class late in the semester I don't know where to begin. Any help is appreciated!!