ANSWER :
[tex]\frac{31z^6}{3}[/tex]
EXPLANATION :
Note that in dividing expressions, the exponents are subtracted from each other
(numerator - denominator)
From the problem, we have :
[tex]\begin{gathered} \frac{31z^{11}}{3z^5}=\frac{31z^{11-5}}{3} \\ \\ =\frac{31z^6}{3} \end{gathered}[/tex]