(x-y)的四次方+x(x+y)的三次方-y(y-x)的三次方大神们帮帮忙

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(x-y)的四次方+x(x+y)的三次方-y(y-x)的三次方大神们帮帮忙

(x-y)的四次方+x(x+y)的三次方-y(y-x)的三次方大神们帮帮忙
(x-y)的四次方+x(x+y)的三次方-y(y-x)的三次方大神们帮帮忙

(x-y)的四次方+x(x+y)的三次方-y(y-x)的三次方大神们帮帮忙
(x-y)^4+x(x+y)^3-y(y-x)^3 =(x-y)^4+x(x+y)^3+y(x-y)^3 =(x-y)^3(x-y+y)+x(x+y)^3 =x(x-y)^3+x(x+y)^3 =x[(x-y)^3+(x+y)^2] =x(x^3-3x^2y+3xy^2-y^2+x^3+3x^2y+3xy^2+y^3) =x(2x^3+6xy^2) =2x^4+6xy^3

(y-x)^4+x(x+y)^3-y(y-x)^3 =(y-x)^3[(y-x)-y]+x(x+y)^3 =-x(y-x)^3+x(x+y)^3 =x[(x+y)^3-(y-x)^3] =x{[(x+y)-(y-x)][(x+y)^2+(x+y)(y-x)+(y-x)^2]} =x[2x(x^2+2xy+y^2+y^2-x^2+y^2-2xy+x^2)] =2x^2(x^2+2y^2)