Let $X$ be the poisson random variable such that $P(X = 2) = 9P(X=4) + 90P(X=6)$
find the mean and variance of $X$.
I'm not sure how to approach this problem..am i supposed to multiply each probability by their respective x value and then add them all together? or am i supposed to somehow find out the values of the probabilities first? Not sure how to find the values with just that equation.