Line from slope and point gt5a
先理解 [math]y=mx[/math]，再從平移概念得出 [math]y=mx+c[/math]。
Understand [math]y=mx[/math] first, then get [math]y=mx+c[/math] through translation.
Reference: [url]http://www.hkame.org.hk/html/modules/tinyd2/content/v35/content.htm[/url]
