Answer:
[tex]\dfrac{18}{y} , \forall y \in R, y\neq 0[/tex]
Step-by-step explanation:
A function is undefined when its denominator is equal to zero.
Therefore, to determine where the function is defined, we find out for what values the function is undefined and remove it.
If y=0, the function is Undefined.
Therefore, the function [tex]\dfrac{18}{y}[/tex]is defined for all values of y such that [tex]y \in R, y\neq 0[/tex]