A) 9
B) 18
C) 27
D) 1
Correct Answer: B
Solution :
\[{{x}^{2}}-3x+1=0\] \[\Rightarrow \] \[{{x}^{2}}+1=3x\]\[\Rightarrow \]\[x+\frac{1}{x}=3\] \[\therefore \] \[{{x}^{3}}+\frac{1}{{{x}^{3}}}={{\left( x+\frac{1}{x} \right)}^{3}}-3x\cdot \frac{1}{x}\left( x+\frac{1}{x} \right)\] \[=27-3\times 3=18\]You need to login to perform this action.
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