Question

if x+1/x=3 then find the value of x^3+1/x^3

Answer 1

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Answer 2

${x}^{3} + \frac{1}{ {x}^{3} }$
$= (x + \frac{1}{x} )^{3} - 3 \times x \times \frac{1}{x} \times (x + \frac{1}{x} )$
$= {3}^{3} - 3 \times 3$
$= 27 - 9$
$= 18$