作业帮先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/2
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 16:01:01
![先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/2](/uploads/image/z/1818807-15-7.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80+%E5%86%8D%E6%B1%82%E5%80%BC%3A%5B4%28xy-1%29%5E2-%28xy%2B2%29%282-xy%29%5D1%2F4xy%2C%E5%85%B6%E4%B8%ADx%3D-2%2Cy%3D1%2F2)
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/2
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/2
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/2
[4(xy-1)^2-(xy+2)(2-xy)]1/4xy
=[4(x²y²-2xy+1)-(4-x²y²)]1/4xy
=(4x²y²-8xy+4-4+x²y²)1/4xy
=(5x²y²-8xy)1/4xy
=(5xy-8)1/4x²y²
∵x=-2,y=1/2
∴xy=-1
原式=(-5-8)1/4(-1)²
=-13/4