$${\begin{align} v_f^2 &= v_i^2 + \frac{2 G M}{R_\text{Maa}} (1-\frac{1}{10}) \\ &= \mathrm{(12 \times 10^3\, m/s)^2 + \frac{2 (6,67 \times 10^{-11}\, m^3/kg \cdot s^2)(5,98 \times 10^{24}\, kg )}{6,37 \times 10^6\, m}} \\ &= 2,567 \times 10^8 \mathrm{m^2 /s^2}\end{align}}$$