Question $6-(15$ points$)$

a$)$Fill out the highlighted fields in the table below. What is the value of $n$ in $(Z_n,o+,ox)?$

b$)$Indicate whether $Z_n$ is a field. Explain the reason why by mentioning two important properties we can check from the chart below.

c$)$ What is the inverse of $7$ for addition if there exist an inverse?

d$)$ What is the inverse of $7$ for multiplication if there exist an inverse?

$\backslash$table$[[o+,0,1,2,3,4,5,6,7,8,9$