1 引例解不等式(x-4)(x~2-3x-4)~(1/2)≥0.在一次练习中,几乎所有同学均采用如下解法:原不等式等价于不等式组(?)解之得 x≥4,故原不等式解集为{x|x≥4}.显然,当 x=-1时,原不等式也能成立,因此,以上解答错了.2 探讨一 1 The introductory solution inequality (x-4)(x~2-3x-4)~(1/2)≥0. In an exercise, almost all students use the following solution: The original inequality is equivalent to the inequality group (?) The solution has x ≥ 4, so the original inequality solution set {x | x ≥ 4}. Obviously, when x = -1, the original inequality can also be established, therefore, the above solution is wrong.2