用因式分解法解高次方程,(1)x^3+2x^2-3=0 (2)x^3-x-6=0
问题描述:
用因式分解法解高次方程,(1)x^3+2x^2-3=0 (2)x^3-x-6=0
用因式分解法解高次方程,
(1)x^3+2x^2-3=0
(2)x^3-x-6=0
答
(1)x^3+2x^2-3=(x³-1)+2x²-2=(x-1)(x²+x+1)+2(x-1)(x+1)
=(x-1)(x²+3x+3)=0 x²+3x+3=0中判别式△=9-12