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by sanjana » Thu Oct 08, 2009 3:56 am
IMO : 2X-3

((x-3)^4)^1/4 = (x-3)

(-x|x|)^1/2

Since x<0 , -x will be same as x
|x| will be = x,even though x is -ve

Hence,(-x|x|)^1/2 = (x^2)^1/2 = x

hence, x-3+x = 2x-3
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by engg.manik » Fri Oct 09, 2009 7:42 am
NO the correct answer is 3-2x
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by sanjana » Fri Oct 09, 2009 7:45 am
Can Someone help?
Not sure where I went wrong!
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by nithi_mystics » Fri Oct 09, 2009 8:01 am
Sanjana,

Your solution is also right but if it is not there as one of our answer options, we'll have to check if there is any other way to solve the equation.

Now,

((x-3)^4)^1/4 = (x-3) or (3-x)

Thats because (x-3)^4 = (3-x)^4

Similarly (-x|x|)^1/2 = x or -x

So, ((x-3)^4)^1/4 + (-x|x|)^1/2 can two solutions.

1) x-3+x = 2x-3
2) 3-x-x = 3-2x

The answer choice should have any one of these.

Hope I am clear.
Thanks
Nithi
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