因式分解(x²-9)(x-1)+(x-3)(x²+3x+6)?

(x-3)(x+3)(x-1)+(x-3)(x²+3x+6)
= (x-3)(x²+2x-3)+(x-3)(x²+3x+6)
= (x-3)(2x²+5x+3)
= (x-3)(2x+3)(x+1)

這是作業嗎@@，錯了不負責喔~

Sol
(x^2－9)(x－1)+(x－3)(x^2+3x+6)
=(x－3)[(x+3)(x－1)+(x^2+3x+6)]
=(x－3)(x^2+2x－3+x^2+3x+6)
=(x－3)(2x^2+5x+3)
=(x－3)(2x+1)(x+1)