1.
x^4+y^4=x^4-2(xy)²+y^4+2(xy)²
=(x²-y²)²+2(xy)²
=(x-y)²(x+y)²+2(xy)²
=(x-y)²[(x-y)²+4xy]+2(xy)²
=8*[8+4*2]+2*4
=136
2.x^4+y^4=(x^2+y^2)^2-2（xy）^2
x^2+y^2=(x+y)^2-2xy
可解得：xy=3
x^4+y^4=82
3.x^2+1/x^2=(x+1/x)^2-2=14
;②(x-1/x)^2=(x+1/x)^2-4=12