因式分解： ①（x+y)^5-x^5-y^5 ②（x+y)^4-x^4-y^4

因式分解：
①（x+y)^5-x^5-y^5
②（x+y)^4-x^4-y^4

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①
(x+y)^5=x^5+5x^4y+10x^3x^2+10x^2y^3+5xy^4+y^5
所以闹培，
原式=5x^4y+10x^3y^2+10x^2y^3+5xy^4
=5xy(x^3+2x^2y+2xy^2+y^3)
=5xy(x+y)(x^2+xy+y^2)

②
(x+y)^4=x^4+4x^3y+6x^2x^2+4xy^3+y^4
所液迅唯以，
原式昌李=4x^3y+6x^2y^2+4xy^2
=2xy(2x^2+3xy+2y^2)

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