Khan/khan-exercises — Issue #11994: Multiplying expressions 1 - (−2x−9)(2x+7)= ?
Author: KhanBugz
Created: 2012-01-24 16:33:26+00:00
State: open
Labels: firefox, win7, wrong-or-unclear

Reporter: fantasycomedian@gmail.com

It seems the correct answer would be None of the Above. I calculated it and turned out with a different solution.

-36x-63

~~~

-2x - 9
X 2x + 7
--------
-14x - 63
-4x - 18x
--------
-36x - 63

OR

~~~

(−2x−9)(2x+7)= ?

(-2x - 9)2x (-2x - 9)7

(-4x) + (-14x) + (-18x) + (-63)

ANSWER~ -36x-63

KhanAcademy Answer~ −4x2−32x−63

[multiplying_expressions_1.html?seed=82&problem=0](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/multiplying_expressions_1.html?seed=82&problem=0&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/multiplying_expressions_1.html?seed=82&problem=0&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%22None%20of%20the%20above.%5C%22%22%2C124%5D%2C%5B%22hint-activity%22%2C%220%22%2C395%5D%2C%5B%22hint-activity%22%2C%220%22%2C396%5D%2C%5B%22hint-activity%22%2C%220%22%2C396%5D%2C%5B%22hint-activity%22%2C%220%22%2C396%5D%2C%5B%22hint-activity%22%2C%220%22%2C397%5D%2C%5B%22hint-activity%22%2C%220%22%2C397%5D%5D)

["None of the above."]

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1

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