-2x³-14x²+10x+150
=-2(x³+7x²-5x-75)
=-2(x³+5x²+2x^2+10x-15x-75)
=-2[(x³+5x²)+(2x^2+10x)-(15x+75)]
=-2[x^2(x+5)+2x(x+5)-15(x+5)]
=-2(x+5)(x^2+2x-15)
=-2(x+5)(x+5)(x-3)
=-2(x+5)^2(x-3)就是-2(x-3)（x+5）²?多谢