Aptitude | Algebra | Question 7

If x^1/3 + y^1/3 – z^1/3 = 0 then value of (x + y – z)³ + 27xyz is
(A) 8
(B) 2
(C) 0
(D) 6

Answer: (C)
Explanation:

x1/3 + y1/3 = z1/3
Now cubing both sides we get 
x + 3x1/3y1/3(x1/3 + y1/3) + y = z
or, (x + y - z) = -3x1/3y1/3z1/3
Cubing again both sides, (x + y - z) = -27xyz.
So answer is zero

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