[quote=Legend]
One in which you may actually use it, or a very specific one such as a crane operator?
[/quote]

Almost always something in which you'd actually use it. Here's an example from my Beginning Algebra book, Lesson 55: Solving Quadratic Equations by Factoring:

Heading back to the bunkhouse, Fred noticed that the eleven recruits had stopped watching television. They were engaged in something more constructive. On this sunny Sunday afternoon they were tearing a hole in the side of the bunkhouse. It was a nice big square hole. Fred stopped to watch. Everyone seemed busy. Pat was swinging a sledgehammer. Two of the guys were standing outside as lookouts. Fred guessed that they hadn't received permission to remodel their quarters. The only one not working on making the hole was Jack. Fred could see him through the hole in the wall. Jack was on the other side of the room working out with his weights.

Chris was on the phone with Waddle Windows (a subsidiary of Waddle Doughnuts). She was finding out the availability of various sizes of windows, and after several minutes of discussion, she ordered the largest one they offered. (Their motto is "A Wot of Window for a Wittle Price is What You Want at Waddle's.")

"You gotta make the hole a lot larger," she told Pat. "Six feet taller and six feet wider. The guy from Waddle said that that would let in four times as much light as what we've got now."

Fred decided not to go inside. He didn't want to be near what he thought might be a crime scene. He went and sat under a tree and thought about what he had heard: [i]It was a square. If it was made six feet larger in each dimension, its area would quadruple.[/i] Was that enough information to find the current dimensions of the hole? Sometimes real life gives you enough information to solve a problem and sometimes it doesn't.

Here's where it starts talking about solving quadratic equations, but with factoring. (I can't actually solve them yet, I just turned to this page for an example.)