Answer
$E=10^{(3R/2)+11.8}$
Work Step by Step
$ R=\displaystyle \frac{2}{3}(\log E-11.8), \qquad /\displaystyle \times\frac{3}{2}$
$\displaystyle \frac{3R}{2}=\log E-11.8\qquad /+11.8$
$\displaystyle \frac{3R}{2}+11.8=\log E\qquad /10^{(...)}$
$E=10^{(3R/2)+11.8}$
