Khan/khan-exercises — pull request #15445 by mathiash (2012-03-05 17:04:07+00:00)
Title: Two exercises on simplifying expressions + minor fixes to ast formatting

The two exercises are basically two versions of the same exercise, but at a different level of difficulty.

Basically, given an expression such as 42xy^2 + 18yz, the exercise asks you to factor this expression by finding the common factors.

In the first exercise, there are only 2 terms, while in the second, there are 3 terms, and each term can be a little bit more complicated.