A) 9
B) 10
C) 27
D) 7
Correct Answer: D
Solution :
Ans. \[x+\frac{1}{x}=3\] \[\Rightarrow \] \[{{\left( x+\frac{1}{x} \right)}^{2}}={{(3)}^{2}}\] \[\Rightarrow \] \[{{x}^{2}}+\frac{1}{{{x}^{2}}}+2x\cdot \frac{1}{x}=9\Rightarrow \,\,{{x}^{2}}+\frac{1}{{{x}^{2}}}+2=9\] \[\therefore \] \[{{x}^{2}}+\frac{1}{{{x}^{2}}}=7\]You need to login to perform this action.
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