A) 18
B) 19
C) 20
D) 21
Correct Answer: B
Solution :
\[x-\frac{1}{x}=\frac{1}{3},\] Multiply both sides by \[3x-\frac{3}{x}=1\Rightarrow 9{{x}^{2}}+\frac{9}{{{x}^{2}}}-2.3x.\frac{3}{x}=1\] \[\Rightarrow \,\,9{{x}^{2}}+\frac{9}{{{x}^{2}}}=1+18=\]You need to login to perform this action.
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