Question

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

Answer 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

追问

谢了

追答

不客气，记得采纳

Answer 2

x²=（-1/2）²=1/4 xy=-1/2 x²y=1/4
原式=4*1/4-[6(-1/2)-2(4(-1/2-2))-1/4]+1
=1-[-3-2(-2-2)-1/4]+1
=1-[5-1/4]+1
=-3+1/4
=-2又3/4
望采纳！