A-2B
=2x²+3xy+2y-1-2(x²-xy+x-1/2)
=2x²+3xy+2y-1-2x²+2xy-2x+1
=5xy-2x+2y
=x(5y-2)+2y
根据题意,结果与x的取值无关
则含x的项为0,
所以,5y-2=0
5y=2
y=五分之二