$E^o\large\frac{A^{+3}}{A^+}$$=xV,E^o\large\frac{A^{+3}}{A^{+2}}$$=yV,E\large\frac{A^{+2}}{A^+}=$?

Question

$\begin{array}{1 1}(a)\;2x-y&(b)\;x\\(c)\;y&(d)\;x-y\end{array}$