Former? =DX+(EX)? = 1+ 1=2
EY? =DY+(EY)? =4+4=8
ρ(XY)=Cov(X,Y)/√(DXDY)=(EXY-EXEY)/2
Therefore exy = 2ρ (xy)+exy =1.2+2 = 3.2.
So EZ=4EX? -4EXY+EY? +4EX-2EY+ 1
=8- 12.8+8+4-4+ 1
=4.2
You can ask questions if you don't understand. If it helps, please choose the satisfactory answer!