please help me to answer 2.1 please!

2. A simple random sample of size n = 15 is drawn from a distribution with probability density function fy = 3(1 -y)2, 2.1. Compute the expectation and the variance of Y. Show and justify your calcula- tions . Hint: Recall that Var(X ) = E(X - Ax )? = E( X ?) - 3. with Ax = E(X)