x*y = 4
x - y = 2
-1.23606797749979
-3.23606797749979
3.23606797749979
1.23606797749979
x1 = 3.23606797749979 y1 = 1.23606797749979
x2 = -1.23606797749979 y2 = -3.23606797749979