作业帮当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 14:15:57
![当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值](/uploads/image/z/1072722-66-2.jpg?t=%E5%BD%93x%3D3%2Cy%3D-1%2F3%E6%97%B6%2C%E6%B1%82%E5%A4%9A%E9%A1%B9%E5%BC%8F3x%26sup2%3By-%5B2xy%26sup2%3B-2%28xy-3%2F2x%26sup2%3By%29%2Bxy%5D%2B3xy%26sup2%3B%E7%9A%84%E5%80%BC)
当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
原式=3X²Y-2XY²+2XY-3X²Y-XY+3XY²
=(3-3)X²Y+(3-2)XY²+(2-1)XY
=XY²+XY
=XY(Y+1)
∵X=3 Y=-1/3
∴原式=3×(-1/3)(-1/3+1)
=-1×2/3
=-2/3
原式=xy2+xy
=1/3-1
=-2/3