Look in your equations. Their left sides are identical. Hence, their right sides must be equal: x + 7 = 6x + 7 It is simple and standard equation in one unknown, and the rest is TRIVIAL: x = 6x ====> 6x - x = 0 ====> 5x = 0 ====> x = 0. Answer. The solution is x = 0, y = 7.