原式=x²+2x-12x-24
=x(x+2)-12(x+2)
=(x+2)(x-12)再问几道好了-0-1.5a+3[2b-3（a-b+2c)-(b+c)]2.4x²-[2x-（x²-2x+3）-2（x²-3x）]采纳我，重新问