The Solution:
Given:
[tex]\begin{gathered} \frac{z^2-x}{z+3x} \\ \\ \text{ Where }x=5,\text{ and }z=7 \end{gathered}[/tex]We are asked to simplify as much as possible.
[tex]\frac{7^2-5}{7+3(5)}=\frac{49-5}{7+15}=\frac{44}{22}=\frac{2}{1}=2[/tex]Therefore, the correct answer is 2.