First we add up all the 'x' terms. So the equation 7 - 4x = x + 8 becomes 7 - 4x - x = x +8 - x => 7 - 5x = 8. Now we can do the same with the other terms. The equation now becomes 7 - 5x - 7 = 8 - 7 => - 5x = 1. The final step we must divide both sides by - 5 to solve for 'x'. Where we get x = -1/5.