已知:3|x+1|+2(y-1)^2=0,求多项式(x^2+4xy-2y^2)-(x^2+y)-2(y^2+xy)-1/

3|x+1|+2(y-1)^2=0
x+1=0
y-1=0
x=-1
y=1
(x^2+4xy-2y^2)-(x^2+y)-2(y^2+xy)-1/2(x-8y^2)
=x^2+4xy-2y^2-x^2-y-2y^2-2xy-1/2x+4y^2
=2xy-1/2x
=2*(-1)*1-1/2*(-1)
=-2+1/2
=-3/2