They want you solve this system of two equations in two unknowns y = -x + 7 y = x + 1. Add these equations (side by side). You will get 2y = 7 + 1 2y = 8 y = 8/2 = 4. Now substitute this found value y= 4 into the second given equation. You will get 4 = x + 1. It implies 4 - 1 = x. x = 3. ANSWER. The solution to the given problem is x= 3, y= 4. You may check that the solution is correct by substituting the values into the original equations.