由x²+y²=6,xy=2,x²y²=4
∴(x²+y²)²=36
x^4+2x²y²+y^4=36
x^4-x²y²+y^4=36-12=24
x^6+y^6=(x²+y²)(x^4-x²y²+y^4)
=6×24
=144.