If the binding energy of ground state electron in a hydrogen atom...

Given:

Binding energy, ${E}_{H} = {E}_{0} = 13 . 6eV$.

Now for hydrogen like atom, we can write

$E{Li}^{2 +} = {E}_{0}\dfrac{{Z}^{2}}{{n}^{2}} = 13 . 6 \times \dfrac{9}{9} = 13 . 6eV$

$= 136 \times {10}^{- 1}eV$

Therefore, $x = 136$.