A) 5
B) 6
C) 8
D) 10
Correct Answer: A
Solution :
\[x={{2}^{1/3}}+{{2}^{-1/3}}\] On cubing both sides, we get \[{{x}^{3}}=2+{{2}^{-1}}+3({{2}^{1/3}}+{{2}^{-1/3}})\] \[\Rightarrow \] \[{{x}^{3}}=\frac{4+1}{2}+3x\] \[\Rightarrow \] \[2{{x}^{2}}=5+6x\] \[\Rightarrow \] \[2{{x}^{3}}-6x=5\]You need to login to perform this action.
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