Yuki T,
Non-linear means not straight lines, right? The real-life situations I think of are exponential equations (such at y = x^2). Jimmy wants to hand out fliers. He hands out fliers to two of his friends. He asks his friends to pass out fliers to two of their friends, who in turn will pass them along to two of their friends.
Jimmy - 1
Jimmy's 2 friends - 2
Jimmy's 2 friends 2 friends - 4
16...64...
It grows exponentially. Think pyramid schemes.
Of course, there are other non-linear equations. For example, some people pay rent based on their income. Someone who earns $10,000 might pay 8% while someone who earns $56,000 might pay 14%.
The difference between linear and non-linear is simple- straight lines with no breaks vs. lines that aren't straight or lines that have breaks.
Hope this helps!
