|x-1|+(y-1)²=0
x-1 x=1
y-1=0 y=1
(x²+4xy-2y²)-(x²+y)-2(y²+xy)-½ (x-8y²)
=(1+4-2)-(1+1)-2*(1+1)-0.5*(1-8)
=0.5
|x-1|+(y-1)²=0所以|x-1|=0,(y-1)²=0 x=1 y=1
代入(x²+4xy-2y²)-(x²+y)-2(y²+xy)-½ (1-8)
可得(1+4-2)-2-2(1+1)+7/2=3-2-4+2/7=1/2
重点在算x=1 y=1
由条件知X=1Y=1
带入第二个式子得(1+4-2)-2-2*2-½=3-2-0.5=0.5
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