A) 0
B) 1
C) 3
D) -3
Correct Answer: C
Solution :
(c): \[xy\left( x-y \right)=1\Rightarrow x-y=\frac{1}{xy}\] Cubing both sides, \[{{x}^{3}}-{{y}^{3}}-3xy\left( x-y \right)=\frac{1}{{{x}^{3}}{{y}^{3}}}\] \[\Rightarrow {{x}^{3}}-{{y}^{3}}-3xy\times \frac{1}{xy}=\frac{1}{{{x}^{3}}{{y}^{3}}}\] \[\Rightarrow \frac{1}{{{x}^{3}}{{y}^{3}}}-{{x}^{3}}+{{y}^{3}}=3\]You need to login to perform this action.
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