If $${x^2} + \frac{1}{{{x^2}}} = 7,$$ then the value of $${x^3} + \frac{1}{{{x^3}}}$$ where x > 0 is equal to:
A. 18
B. 12
C. 15
D. 16
Answer: Option A
Solution (By Examveda Team)
$$\eqalign{ & {x^2} + \frac{1}{{{x^2}}} = 7 \cr & x + \frac{1}{x} = 3 \cr & {x^3} + \frac{1}{{{x^3}}} = {3^3} - 3 \times 3 = 18 \cr} $$This Question Belongs to Arithmetic Ability >> Algebra
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