Examveda

If $$\frac{1}{a}\left( {{a^2} + 1} \right) = 3{\text{,}}$$    then the value of $$\frac{{{a^6} + 1}}{{{a^3}}}$$   = ?

A. 9

B. 18

C. 27

D. 1

Answer: Option B

Solution (By Examveda Team)

$$\eqalign{ & \frac{1}{a}\left( {{a^2} + 1} \right) = 3 \cr & \Rightarrow a + \frac{1}{a} = 3 \cr & \Rightarrow {a^3} + \frac{1}{{{a^3}}} + 3.a.\frac{1}{a}\left( {a + \frac{1}{a}} \right) = {3^3} \cr & \Rightarrow {a^3} + \frac{1}{{{a^3}}} + 3\left( 3 \right) = {3^3} \cr & \Rightarrow {a^3} + \frac{1}{{{a^3}}} = 27 - 9 \cr & \Rightarrow {a^3} + \frac{1}{{{a^3}}} = 18 \cr & \Rightarrow \frac{{{a^6} + 1}}{{{a^3}}} = 18 \cr} $$

This Question Belongs to Arithmetic Ability >> Algebra

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