A) -52
B) 52
C) 18
D) -18
Correct Answer: C
Solution :
(c): \[{{\left( 3x+\frac{1}{3x} \right)}^{3}}=27{{x}^{3}}+\frac{1}{27{{x}^{3}}}+3\left( 3x+\frac{1}{3x} \right)\] \[{{\left( 3 \right)}^{3}}=27{{x}^{3}}+\frac{1}{27{{x}^{3}}}+3\left( 3x+\frac{1}{3x} \right)\] \[\therefore 27{{x}^{3}}+\frac{1}{27{{x}^{3}}}=27-9=18\]You need to login to perform this action.
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