求值:4x²y-[6xy-2(4xy-2)-x²y]+1,其中x=-1/2

问题描述:

求值:4x²y-[6xy-2(4xy-2)-x²y]+1,其中x=-1/2

x=-1/2
4x²y-[6xy-2(4xy-2)-x²y]+1
=5x²y-6xy+2(4xy-2)+1
=5x²y+2xy-3
=5/4y-y-3
=y/4-3