作业帮4x²y-[6xy-3(4xy-2)-x²y]+1的值,其中x=2,y=-二分之一
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/12 16:21:39
![4x²y-[6xy-3(4xy-2)-x²y]+1的值,其中x=2,y=-二分之一](/uploads/image/z/1064846-38-6.jpg?t=4x%26%23178%3By-%5B6xy-3%284xy-2%29-x%26%23178%3By%5D%2B1%E7%9A%84%E5%80%BC%2C%E5%85%B6%E4%B8%ADx%3D2%2Cy%3D-%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80)
4x²y-[6xy-3(4xy-2)-x²y]+1的值,其中x=2,y=-二分之一
4x²y-[6xy-3(4xy-2)-x²y]+1的值,其中x=2,y=-二分之一
4x²y-[6xy-3(4xy-2)-x²y]+1的值,其中x=2,y=-二分之一
4x²y-[6xy-3(4xy-2)-x²y]+1
=4x²y-6xy+3(4xy-2)+x²y+1
=5x²y+6xy-5
=5×4×（-1/2）+6×2×（-1/2）-5
=-10-6-5
=-21
4x²y-[6xy-3(4xy-2)-x²y]+1=4x²y-[6xy-12xy+6-x²y]+1=4x²y-6xy+12xy-6+x²y+1
=5x²y+6xy-5
把x=2,y=-二分之一 代入，原式＝－10－6－5＝－21