$x^2 \int $
When $a \ne 0$, there are two solutions to (ax^2 + bx + c = 0) and they are $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
posted on 2018-03-18 20:11 邵玉斌 阅读(100) 评论(0) 编辑 收藏 举报
