Answer
$$3,52 X 10^{-25}N$$
Work Step by Step
$F=\frac{k\times q_{1}\times q_{2}}{(d^{2})}-\frac{k\times q_{1}\times q_{3}}{(2d^{2})}-\frac{k\times q_{1}\times q_{4}}{(3d^{2})}$
$=\frac{k\times 2\times e^{2}}{d^{2}}-\frac{k\times 2\times e^{2}}{4d^{2}}-\frac{k\times 8\times e^{2}}{9d^{2}}$
$=\frac{(72-18-32)\times k\times e^{2}}{36d^{2}}$
$=\frac{22\times9\times10^{9}\times (1,6\times10^{19})^{2}}{36\times(2\times10^{-2})^{2}}$
$=\frac{506,88\times10^{-29}}{144\times10^{-4}}$
$=3,52\times10^{-25}N$
