Given that [latex]E\left( X \right)=3[/latex], [latex]\text{Var}\left( X \right)=4[/latex], [latex]\text{E}\left( Y \right)=-2[/latex]and [latex]\text{Var}\left( Y \right)=7[/latex] . Find the expectation and variance of
(i)
[latex]3X+2Y[/latex]
(ii)
[latex]2X-3Y[/latex]
(iii)
[latex]{{X}_{1}}+{{X}_{2}}-{{Y}_{1}}-{{Y}_{2}}-{{Y}_{3}}[/latex]