[kamaal]

>>I mean if a test asks you to solve 3x^2+5+2x=7, how do you solve it without know the quadratic formula or some such?

If you have memorized the general heuristic to solve any particular equation, its basically that is all there is to solving that equation. What is left after that is to practice that algorithm enough number of times until it just comes to you naturally when you see such equation again.

Richard Feynman, noted people find math difficult because all the while they are focusing on just that 'memorizing that algorithm' part. He used to call this as 'for people who don't know what they are doing'.

In school, or even in college, there are only a finite number of such algorithms to rote memorize. If you do, and practice those problem enough number of time, you can essentially score big marks in the exam.

Unfortunately the same is in software interviews these days. The most common algorithm experts you come across these days, are exactly algorithm experts. These are simply people who can recall all the algorithms they have rote memorized earlier. I know of people who spend dedicated time every day memorizing time and space complexity of many commonly asked interview algorithms on flash cards.

Ironically hiring such candidates at times is almost synonymous with hiring bad candidates.