1.0 link Rainbow Dash Network http://rainbowdash.net/ aaaaaaaaaa (aaaaaaaaa) http://rainbowdash.net/aaaaaaaaa http://rainbowdash.net/notice/146146 @<span class="vcard"><a href="http://rainbowdash.net/user/148" class="url" title="Zambo"><span class="fn nickname">carcinopony</span></a></span> I'm sorry. I think I may have gone overboard using function notation - I think that's introduced in Grade 11 in most North American schoolboards. Let me try again: You're probably used to seeing linear equations in the &quot;y = mx + b&quot; form. &quot;m&quot; is your slope, or rate of change. In the finance example, the &quot;rate of change&quot; at which your wealth changes is simply your payrate, or $200 per week. The &quot;b,&quot; is the y-intercept, or you can also think of it as an &quot;initial value.&quot; Since you start with $500 saved, then b = 500. Thus, to determine your wealth in that example, the linear equation should be y = 200x + 500. Is that explanation clearer?