“计算(2x^3-3x^2y-xy^2)+(-x^3+2x^2y+y^3)-(x^3-x^2y-xy^2)的值,其中x=二分之一,y=-1".甲同学把“x=二分之一“错抄成”x=-二分之一,但他计算结果也是正确的,试说明理由,并求出这个结果
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/02 09:06:14
![“计算(2x^3-3x^2y-xy^2)+(-x^3+2x^2y+y^3)-(x^3-x^2y-xy^2)的值,其中x=二分之一,y=-1](/uploads/image/z/2582150-14-0.jpg?t=%E2%80%9C%E8%AE%A1%E7%AE%97%282x%5E3-3x%5E2y-xy%5E2%29%2B%28-x%5E3%2B2x%5E2y%2By%5E3%29-%28x%5E3-x%5E2y-xy%5E2%29%E7%9A%84%E5%80%BC%2C%E5%85%B6%E4%B8%ADx%3D%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%2Cy%3D-1%22.%E7%94%B2%E5%90%8C%E5%AD%A6%E6%8A%8A%E2%80%9Cx%3D%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%E2%80%9C%E9%94%99%E6%8A%84%E6%88%90%E2%80%9Dx%3D-%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%2C%E4%BD%86%E4%BB%96%E8%AE%A1%E7%AE%97%E7%BB%93%E6%9E%9C%E4%B9%9F%E6%98%AF%E6%AD%A3%E7%A1%AE%E7%9A%84%2C%E8%AF%95%E8%AF%B4%E6%98%8E%E7%90%86%E7%94%B1%2C%E5%B9%B6%E6%B1%82%E5%87%BA%E8%BF%99%E4%B8%AA%E7%BB%93%E6%9E%9C)
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