(4x的3次方-31x+15)怎么解,
问题描述:
(4x的3次方-31x+15)怎么解,
答
4X^3-31X+15=x(4x^2-25)-6x+15=(2x-5)(2x^2+5x-3)=(2x-5)(x+3)(2x-1)
X^3+5X^2+3X-9=(x-1)(x+3)^2