Khan/khan-exercises — Issue #15647: Solving for a variable - SWAP SIGNS SO DENOM ISN'T NEGATIVE
Author: KhanBugz
Created: 2012-03-07 17:18:53+00:00
State: open
Labels: chrome, hard, win7

Reporter: daddo.rocket@gmail.com

6 problems ago my answer was "wrong" because it said my answer:
-2b-11/8b-5c+9 wasn't simplified to:
2b+11/-8b+5c-9 but your "simplified"
answer has a negative denominator.
So which is it? Is a negative denom always bad here?

[solving_for_a_variable.html?seed=58&problem=ABC_DEF](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/solving_for_a_variable.html?seed=58&problem=ABC_DEF&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/solving_for_a_variable.html?seed=58&problem=ABC_DEF&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%22None%20of%20the%20above.%5C%22%22%2C203%5D%2C%5B%22hint-activity%22%2C%220%22%2C55%5D%2C%5B%22hint-activity%22%2C%220%22%2C62%5D%2C%5B%22hint-activity%22%2C%220%22%2C66%5D%2C%5B%22hint-activity%22%2C%220%22%2C81%5D%2C%5B%22hint-activity%22%2C%220%22%2C89%5D%2C%5B%22hint-activity%22%2C%220%22%2C115%5D%2C%5B%22hint-activity%22%2C%220%22%2C123%5D%2C%5B%22hint-activity%22%2C%220%22%2C149%5D%2C%5B%22hint-activity%22%2C%220%22%2C166%5D%2C%5B%22hint-activity%22%2C%220%22%2C178%5D%2C%5B%22hint-activity%22%2C%220%22%2C183%5D%2C%5B%22hint-activity%22%2C%220%22%2C198%5D%2C%5B%22hint-activity%22%2C%220%22%2C207%5D%2C%5B%22hint-activity%22%2C%220%22%2C217%5D%2C%5B%22hint-activity%22%2C%220%22%2C226%5D%2C%5B%22correct-activity%22%2C%22%5C%22%3Ccode%20style%3D%5C%5C%5C%22display%3A%20none%3B%20%5C%5C%5C%22%3El%20%3D%20%5C%5C%5C%5Cdfrac%7B-20n%20-%208m%7D%7B9%7D%3C%2Fcode%3E%5C%22%22%2C338%5D%5D)

["None of the above.","l = \\dfrac{-20n - 8m}{9}"]

Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.66 Safari/535.11

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