求方程x3+x2-8x-8=0 用因式分解法求方程的根
问题描述：
求方程x3+x2-8x-8=0 用因式分解法求方程的根
答
x3+x2-8x-8=0 ==> x^3 + x^2 - 8x -8 = 0 ==> x^2(x +1) - 8(x +1) = 0 ==> (x +1)(x^2 - 8) = 0 ==> (x +1)(x + 2√2)(x -2√2) = 0 ==> x =1,-2√2,2√2