tìm x biết: (x-3)^3+(2-2x)^3+(x+1)^3=0

$(x-3)^3+(2-2x)^3+(x+1)^3=0$

$⇔(x-3+x+1)[(x-3)^2-(x-3)(x+1)+(x+1)^2]+(2-2x)^3=0$

$⇔(2x-2)(x^2-6x+9-x^2+2x+3+x^2+2x+1)-(2x-2)^3=0$

$⇔(2x-2)[x^2-2x+13-(2x-2)^2]=0$

$⇔(2x-2)(x^2-2x+13-4x^2+8x-4)=0$

$⇔(x-1)(-3x^2+6x+9)=0$

$⇔(x-1)(x^2-2x-3)=0$

$⇔(x-1)(x-3)(x+1)=0$

$⇔x=±1;x=3$