# How to find the values of the following forces when it isn't given?

$M_A = 4\left( \frac{3}{5}F_1 \right) - 5\left( \frac{4}{5}F_1 \right) - 1(F_2) + 5\left( \frac{5}{13}F_3 \right) + 2\left( \frac{12}{13}F_3 \right)$