The number e is a number with a fixed value so it should be treated in an equation like any other number when solving an equation. Add 4x to each side of the equation: 3e^3+5=77+4x, then subtract 77 from each side: 3e^3-72=4x. Evaluate 3e^3 (using a calculator) = 60.2566, so -11.7434=4x, therefore x=-11.7434/4=-2.936.