Solve: negative 1 over 2 x 3 = –x 7

The equation to solve seems to be 1 / (2x) + 3 = - x + 7. Which is solved using this steps: First multiply both sides times 2x (this implies that x cannot be zero). As result you get: -1 + 6x = -2x^2 + 14x. Second group terms in the left side: 2x^2 + 6x - 14x - 1 = 0 => 2x^2 - 8x - 1 = 0. Third, use the quatratic equation to solve and you get two answers: x= -0.121 and x = 4.121

The method to find the female dormitory is 2-d=800