2x²y-[x²y+2（x²y-xy)]+y 其中x²=2x+1 y=2011/2012

来源：学生作业学帮网编辑：学帮网时间：2024/05/10 16:24:11

2x²y-[x²y+2（x²y-xy)]+y
=2x²y-x²y-2x²y+2xy+y
=-x²y+2xy+y
=-y[x²-(2x+1）]
∵x²=2x+1
∴2x²y-[x²y+2（x²y-xy)]+y=0