Khan/khan-exercises — Issue #7149: Adding and subtracting radicals - (2-1+5) does not = 6 
Author: KhanBugz
Created: 2011-11-27 21:49:52+00:00
State: open
Labels: ie8, ie9, win7, wrong-or-unclear

Question:
"Simplify the following expression"
Square root of 52 - square root of 13 + square root of 325.

(2-1+5)sqaure root of 13 = 6 square root of 13.
That does not make any sense.
The answer would be 4 sqaure root of 13.

[adding_and_subtracting_radicals.html?seed=156&problem=three-radicals](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/adding_and_subtracting_radicals.html?seed=156&problem=three-radicals&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/adding_and_subtracting_radicals.html?seed=156&problem=three-radicals&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5B-2%2C13%5D%22%2C123%5D%2C%5B%22incorrect-activity%22%2C%22%5B2%2C13%5D%22%2C6%5D%2C%5B%22incorrect-activity%22%2C%22%5B2%2C13%5D%22%2C4%5D%2C%5B%22hint-activity%22%2C%220%22%2C38%5D%2C%5B%22hint-activity%22%2C%220%22%2C40%5D%2C%5B%22hint-activity%22%2C%220%22%2C45%5D%2C%5B%22hint-activity%22%2C%220%22%2C48%5D%2C%5B%22hint-activity%22%2C%220%22%2C52%5D%2C%5B%22hint-activity%22%2C%220%22%2C54%5D%2C%5B%22correct-activity%22%2C%22%5B6%2C13%5D%22%2C72%5D%5D)

[[-2,13],[2,13],[2,13],[6,13]]

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