计算(x+y)的平方-(x的立方+y的立方)÷(x+y)

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计算(x+y)的平方-(x的立方+y的立方)÷(x+y)

计算(x+y)的平方-(x的立方+y的立方)÷(x+y)
计算(x+y)的平方-(x的立方+y的立方)÷(x+y)

计算(x+y)的平方-(x的立方+y的立方)÷(x+y)
(x+y)^2-(x^3+y^3)/(x+y)
=(x+y)^2-[(x+y)*(x^2-xy+y^2)]/(x+y) PS:x^3+y^3=(x+y)(x^2-xy+y^2)
=(x+y)^2-(x^2-xy+y^2)
=x^2+2xy+y^2-x^2+xy-y^2
=3xy

[(x+y)^2-(x^3+y^3)]/(x+y)
=[(x+y)^2-(x+y)(x^2+y^2-xy)]/(x+y)
=(x+y)^2-(x^2+y^2-xy)
=xy

x^2+2xy+y^2-(x^2-xy+y^2)=3xy