Question

$calculati x^{3} + \frac{1}{ x^{3} } stiind ca x+ \frac{1}{x} =0,(3)$

Answer 1

x + 1 /x = 3 /9 = 1 /3 
( x + 1 /x)³   =  1 / 3³ =1 /27 
x³ + 1 / x³ + 3 ·x ·1/x · ( x + 1 /x ) = 1 /27 
x³ + 1 /x³ +        3   ·      1/3  = 1/27 
x³  + 1 /x³ = 1/27 - 1 =  - 26 /27