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After taking |A|=0, I am getting x3+1=0 and not x3-1=0.
Is it x3+1=0 or x3-1=0?

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|A| = x * ( x*x - 0 ) - (-1)(0 - (-1)(-1)) = 0 [expanding along the first row and |A| should be 0]

=> $x^3 - 1$ = 0

=> x = 1
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Ya, i missed the '-' in multiplying 2nd parameter.

BTW, expansion of (x3-1) is (x-1)(x2+x+1), so x=1, and not -1, for real values of x.

Oh, sorry, that's a typo :P editing the answer.

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