[tex]\orange\bigstar \bold{ solution}[/tex]
[tex]\bold{f(x) = x³ - \frac{1}{x³ } }[/tex]
[tex]\bold{f ( \frac{1}{x} )= \frac{1}{x³} -x³ } [/tex]
[tex]\bold{f (x) + f (\frac{1}{x}) = (x³- \frac{1}{x³} ) + ( \frac{1}{x³} -x³)}[/tex]
[tex]\bold{ = 0 }[/tex]
