Question

x elevado ao cubo = 8/343

Answer 1

$x^3=\frac{8}{343}\\ \\ x^3=(\frac{2}{7})^3\\ \\ Logo:\\ \\ \boxed{x=\frac{2}{7}}$

Answer 2

x³    =   8
          343
x³  = (  2 )³
           7  
x= 2
      7