因式分解：①9（x-3y）3次方+（3y-x） ②3分之1a的2次方-3b2次方 ③a4次方-256b4次方c4次方

①9(x-3y)³+(3y-x)=9(x-3y)³-(x-3y)=(x-3y)[9(x-3y)²-1]=(x-3y)(3x-9y-1)(3x-9y+1)②1/3a²-3b²=1/3(a²-9b²)=1/3(a-3b)(a+3b)③a^4-256b^4c^4=(a²+16b²c²)(a²...