\text { 2. Suppose } X \text { and } Y \text { are r.v.s with } E(X)=7, E\left(X^{2}\right)=70, E(Y)=-2 \text {, and } E\left(Y^{2}\right)=19 \text {. } \text {

(a) Compute } E(6 X-5 Y) \text {. } \text { (b) Compute var }(-4 Y) \text {. } (c) If X and Y are independent, find var(X + Y). (d) If X and Y were not independent, could you find var(X +Y) with the information provided?