please can somebody clear my doubt

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please can somebody clear my doubt

by Win_the_gmat » Sat Apr 13, 2013 2:11 pm
Hi experts,
I would like to know the difference between the 2 equations:
x^2 = 16 and x = sqrt 16
why in the 1st case it has 2 solutions 4 and -4 but in the 2nd case only 1 solution i.e. x = 4.

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by srcc25anu » Mon Apr 15, 2013 1:27 pm
1: sqrt9 = 3
sqrt9 is already a +ve. If it were to be -ve, it would be -(sqrt9).
Therefore, sqrt9 = 3.


2: Every variable has 2 roots: i.e. +ve and -ve. so (x-1)^2= 16 also has the same. i.e.
x - 1 = sqrt16 or -(sqrt16)

i: x - 1 = sqrt16
x - 1 = 4
x = 5

ii: x -1 = -(sqrt16)
x -1 = -(4)
x = -4 + 1
x = -3

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by Jim@StratusPrep » Thu Apr 18, 2013 5:56 am
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