(x - 3/x)^2 = x^2 - 2*x*3/x + 9/x^2 = x^2 + 9/x^2 - 6
x^2 + 9/x^2 = 55
x^2 + 9/x^2 - 6 = 49
(x - 3/x)^2 = 49
x - 3/x = 7
x - 3/x = -7
(x - 3/x)^2 = x^2 - 2*x*3/x + 9/x^2 = x^2 + 9/x^2 - 6
x^2 + 9/x^2 = 55
x^2 + 9/x^2 - 6 = 49
(x - 3/x)^2 = 49
x - 3/x = 7
x - 3/x = -7