You've proceeded correctly so far! Continue from the last equation -2X+(60/X) = 7 Multiplying by x -2*x^2 + 60 = 7*xThis is a standard quadratic equation which can be solved by factorizing So the 2 roots are 2*x + 15 = 0, or x = -15/2 x - 4 = 0, or x = 4 Hope you got it :)