[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.65,0:00:02.70,Default,,0000,0000,0000,,要解二次方程 －3x 的平方加上
Dialogue: 0,0:00:02.70,0:00:07.62,Default,,0000,0000,0000,,10x 减去 3 等于 0。
Dialogue: 0,0:00:07.62,0:00:09.56,Default,,0000,0000,0000,,这个方程已经是标准式了。
Dialogue: 0,0:00:09.56,0:00:11.06,Default,,0000,0000,0000,,有很多解法。
Dialogue: 0,0:00:11.06,0:00:13.60,Default,,0000,0000,0000,,如果采用二次方程求解的公式一定可以解出来。
Dialogue: 0,0:00:13.60,0:00:14.68,Default,,0000,0000,0000,,我把方程抄下来。
Dialogue: 0,0:00:14.68,0:00:19.44,Default,,0000,0000,0000,,方程为－3x 的平方加上 10x 减去 3 等于 0。
Dialogue: 0,0:00:19.44,0:00:20.81,Default,,0000,0000,0000,,我打算用二次方程的公式
Dialogue: 0,0:00:20.81,0:00:22.72,Default,,0000,0000,0000,,来解两次，以说明只要我们
Dialogue: 0,0:00:22.72,0:00:25.35,Default,,0000,0000,0000,,正确地使用公式，
Dialogue: 0,0:00:25.35,0:00:26.85,Default,,0000,0000,0000,,就一定能得到该
Dialogue: 0,0:00:26.85,0:00:29.90,Default,,0000,0000,0000,,方程的正确且
Dialogue: 0,0:00:29.90,0:00:31.37,Default,,0000,0000,0000,,一致的解答。
Dialogue: 0,0:00:31.37,0:00:34.32,Default,,0000,0000,0000,,在眼前这个格式的方程里面, a, b, c 是多少？
Dialogue: 0,0:00:34.32,0:00:36.78,Default,,0000,0000,0000,,我们先来谈谈二次方程
Dialogue: 0,0:00:36.78,0:00:37.45,Default,,0000,0000,0000,,的解题公式是什么。
Dialogue: 0,0:00:37.45,0:00:38.73,Default,,0000,0000,0000,,从这里开始比较好。
Dialogue: 0,0:00:38.73,0:00:40.64,Default,,0000,0000,0000,,二次方程的解题公式
Dialogue: 0,0:00:40.64,0:00:43.17,Default,,0000,0000,0000,,就是面对一个二次方程，
Dialogue: 0,0:00:43.17,0:00:48.32,Default,,0000,0000,0000,,格式为 a x 平方加上 b x 再加上 c 等于 0，就是用标准格式来表示，
Dialogue: 0,0:00:48.32,0:00:52.36,Default,,0000,0000,0000,,它的解就是 x 等于 －b
Dialogue: 0,0:00:52.36,0:00:55.63,Default,,0000,0000,0000,,加上或减去 b 的平方减去 4a c的平方根，
Dialogue: 0,0:00:55.63,0:01:02.43,Default,,0000,0000,0000,,然后再除以 2a。
Dialogue: 0,0:01:02.43,0:01:05.24,Default,,0000,0000,0000,,而这个公式源于解二次方程的
Dialogue: 0,0:01:05.24,0:01:06.41,Default,,0000,0000,0000,,构建平方法。
Dialogue: 0,0:01:06.41,0:01:09.91,Default,,0000,0000,0000,,因此这个方法并不深奥，我在其它的视频里已经推导过了。
Dialogue: 0,0:01:09.91,0:01:11.33,Default,,0000,0000,0000,,这就是解二次方程的公式。
Dialogue: 0,0:01:11.33,0:01:12.91,Default,,0000,0000,0000,,这个公式可以得到两个解，
Dialogue: 0,0:01:12.91,0:01:14.89,Default,,0000,0000,0000,,因为这里有正负
Dialogue: 0,0:01:14.89,0:01:16.68,Default,,0000,0000,0000,,两个平方根。
Dialogue: 0,0:01:16.68,0:01:19.75,Default,,0000,0000,0000,,在这里把它应用于本例 － 本例里面，
Dialogue: 0,0:01:19.75,0:01:26.89,Default,,0000,0000,0000,,a 等于 －3，b 等于 10，
Dialogue: 0,0:01:26.89,0:01:31.00,Default,,0000,0000,0000,,c 等于 －3。
Dialogue: 0,0:01:31.00,0:01:33.24,Default,,0000,0000,0000,,
Dialogue: 0,0:01:33.24,0:01:36.53,Default,,0000,0000,0000,,
Dialogue: 0,0:01:36.53,0:01:37.53,Default,,0000,0000,0000,,
Dialogue: 0,0:01:37.53,0:01:42.80,Default,,0000,0000,0000,,
Dialogue: 0,0:01:42.80,0:01:44.69,Default,,0000,0000,0000,,
Dialogue: 0,0:01:44.69,0:01:45.46,Default,,0000,0000,0000,,
Dialogue: 0,0:01:45.46,0:01:50.65,Default,,0000,0000,0000,,
Dialogue: 0,0:01:50.65,0:01:54.39,Default,,0000,0000,0000,,
Dialogue: 0,0:01:54.39,0:01:55.47,Default,,0000,0000,0000,,
Dialogue: 0,0:01:55.47,0:01:58.93,Default,,0000,0000,0000,,
Dialogue: 0,0:01:58.93,0:02:01.10,Default,,0000,0000,0000,,
Dialogue: 0,0:02:01.10,0:02:02.86,Default,,0000,0000,0000,,
Dialogue: 0,0:02:02.86,0:02:05.54,Default,,0000,0000,0000,,
Dialogue: 0,0:02:05.54,0:02:07.66,Default,,0000,0000,0000,,
Dialogue: 0,0:02:07.66,0:02:14.71,Default,,0000,0000,0000,,
Dialogue: 0,0:02:14.71,0:02:16.08,Default,,0000,0000,0000,,
Dialogue: 0,0:02:16.08,0:02:18.28,Default,,0000,0000,0000,,
Dialogue: 0,0:02:18.28,0:02:19.53,Default,,0000,0000,0000,,
Dialogue: 0,0:02:19.53,0:02:21.61,Default,,0000,0000,0000,,
Dialogue: 0,0:02:21.61,0:02:23.86,Default,,0000,0000,0000,,
Dialogue: 0,0:02:23.86,0:02:27.31,Default,,0000,0000,0000,,
Dialogue: 0,0:02:27.31,0:02:31.83,Default,,0000,0000,0000,,
Dialogue: 0,0:02:31.83,0:02:33.90,Default,,0000,0000,0000,,
Dialogue: 0,0:02:33.90,0:02:35.94,Default,,0000,0000,0000,,
Dialogue: 0,0:02:35.94,0:02:38.23,Default,,0000,0000,0000,,
Dialogue: 0,0:02:38.23,0:02:43.94,Default,,0000,0000,0000,,
Dialogue: 0,0:02:43.94,0:02:45.62,Default,,0000,0000,0000,,
Dialogue: 0,0:02:45.62,0:02:48.21,Default,,0000,0000,0000,,
Dialogue: 0,0:02:48.21,0:02:52.56,Default,,0000,0000,0000,,
Dialogue: 0,0:02:52.56,0:02:54.57,Default,,0000,0000,0000,,
Dialogue: 0,0:02:54.57,0:02:56.33,Default,,0000,0000,0000,,
Dialogue: 0,0:02:56.33,0:02:58.94,Default,,0000,0000,0000,,
Dialogue: 0,0:02:58.94,0:03:00.84,Default,,0000,0000,0000,,
Dialogue: 0,0:03:00.84,0:03:04.61,Default,,0000,0000,0000,,
Dialogue: 0,0:03:04.61,0:03:08.03,Default,,0000,0000,0000,,
Dialogue: 0,0:03:08.03,0:03:10.07,Default,,0000,0000,0000,,
Dialogue: 0,0:03:10.07,0:03:13.49,Default,,0000,0000,0000,,
Dialogue: 0,0:03:13.49,0:03:16.93,Default,,0000,0000,0000,,
Dialogue: 0,0:03:16.93,0:03:19.38,Default,,0000,0000,0000,,
Dialogue: 0,0:03:19.38,0:03:22.49,Default,,0000,0000,0000,,
Dialogue: 0,0:03:22.49,0:03:24.70,Default,,0000,0000,0000,,
Dialogue: 0,0:03:24.70,0:03:25.74,Default,,0000,0000,0000,,
Dialogue: 0,0:03:25.74,0:03:27.28,Default,,0000,0000,0000,,
Dialogue: 0,0:03:27.28,0:03:30.12,Default,,0000,0000,0000,,
Dialogue: 0,0:03:30.12,0:03:31.88,Default,,0000,0000,0000,,
Dialogue: 0,0:03:31.88,0:03:33.25,Default,,0000,0000,0000,,
Dialogue: 0,0:03:33.25,0:03:37.01,Default,,0000,0000,0000,,
Dialogue: 0,0:03:37.01,0:03:39.27,Default,,0000,0000,0000,,
Dialogue: 0,0:03:39.27,0:03:45.00,Default,,0000,0000,0000,,
Dialogue: 0,0:03:45.00,0:03:46.90,Default,,0000,0000,0000,,
Dialogue: 0,0:03:46.90,0:03:51.99,Default,,0000,0000,0000,,
Dialogue: 0,0:03:51.99,0:03:54.43,Default,,0000,0000,0000,,
Dialogue: 0,0:03:54.43,0:03:56.40,Default,,0000,0000,0000,,
Dialogue: 0,0:03:56.40,0:04:00.56,Default,,0000,0000,0000,,
Dialogue: 0,0:04:00.56,0:04:02.46,Default,,0000,0000,0000,,
Dialogue: 0,0:04:02.46,0:04:05.30,Default,,0000,0000,0000,,
Dialogue: 0,0:04:05.30,0:04:07.95,Default,,0000,0000,0000,,
Dialogue: 0,0:04:07.95,0:04:12.11,Default,,0000,0000,0000,,
Dialogue: 0,0:04:12.11,0:04:16.07,Default,,0000,0000,0000,,
Dialogue: 0,0:04:16.07,0:04:17.98,Default,,0000,0000,0000,,
Dialogue: 0,0:04:17.98,0:04:20.25,Default,,0000,0000,0000,,
Dialogue: 0,0:04:20.25,0:04:21.99,Default,,0000,0000,0000,,
Dialogue: 0,0:04:21.99,0:04:28.03,Default,,0000,0000,0000,,
Dialogue: 0,0:04:28.03,0:04:30.66,Default,,0000,0000,0000,,
Dialogue: 0,0:04:30.66,0:04:32.21,Default,,0000,0000,0000,,
Dialogue: 0,0:04:32.21,0:04:36.42,Default,,0000,0000,0000,,
Dialogue: 0,0:04:36.42,0:04:38.31,Default,,0000,0000,0000,,
Dialogue: 0,0:04:38.31,0:04:41.30,Default,,0000,0000,0000,,
Dialogue: 0,0:04:41.30,0:04:43.10,Default,,0000,0000,0000,,
Dialogue: 0,0:04:43.10,0:04:46.28,Default,,0000,0000,0000,,
Dialogue: 0,0:04:46.28,0:04:50.30,Default,,0000,0000,0000,,