gl1: x^(2) + y^(2) = 3^(2)
REQ: x^4 + y^4 = 81
a: x^4 + 4x^3 y + 6x^2 y^2 + 4x y^3 + y^4 = 81
b: x^4 y^4 = 81
c: x^4 + 2x^2 y^2 + y^4 = 81
d: x^4 + y^4 = 81
e: -x^4 - 18x^2 + y^4 = 81
g: x^4 + 2x^2 y^2 + y^4 = 81
f: x^4 + x^2 y^2 + y^4 = 81
lo: x - y = -3
lu: x + y = -3
ru: x - y = 3
ro: x + y = 3