Answer :
No, you cube all of the numerator and denominator. This is because when you cube anything you do the number multiplied by the number 3 times. So you do the same with fractions.
[tex] \frac{3}{4} * \frac{3}{4} * \frac{3}{4} = \frac{3}{4} ^{3}[/tex]
[tex] \frac{3}{4} * \frac{3}{4} * \frac{3}{4} = \frac{3}{4} ^{3}[/tex]