①根号36-根号3=6-根号3
a=4
b=2-根号3
a-2b=2根号3
②x²-3x+1＝0
x1+x2=3>0
x1x2=1>0
x1,x2>0
x+1/x=3
√x²+1／x+2
=x+1/x+2
=5
③xy=1
x＝（√3）-1／（√3）+1=2-根号3
y=2+根号3
x^4+y^4
=(x^2+y^2)^2-2x^2y^2
=(7+7)^2-2
=194
很高兴为您解答,希望对你有所帮助!
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