4x²y一[6xy一2(4xy-2)-x²y]十1,其中x=一½,y=1.

4x²y一[6xy一2(4xy-2)-x²y]十1,其中x=一½,y=1.
4x²y一[6xy一2(4xy-2)-x²y]十1,其中x=一½,y=1.

4x²y一[6xy一2(4xy-2)-x²y]十1,其中x=一½,y=1.
4x²y-{6xy-2(4xy-2)-x²y}+1 先去掉小括号
=4x²y-(6xy-8xy+4-x²y)+1 再去掉中括号
=4x²y-6xy+8xy-4+x²y+1 合并同类项
=5x²y+2xy-3 代入数据
=5×(-2分之1)²×1+2×(-2分之1)×1-3
=4分之5-1-3
=4分之5-4
=4分之5-4分之16
=-4分之11
=-2又4分之3