kitchen table math, the sequel

• Given that f(x) = 3 x 2 + 2x, find [f(x + h) – f(x)] / h.

This is actually something you will see again in calculus. I guess they're trying to "prep" you for upcoming courses when they give you exercises like this, but it's not like anybody remembers these by the time they get to calculus, so it's really a lot of work for no real purpose. However, this type of problem is quite popular, so you should expect to need to know how to do it.