Answer
$$x = 0{\text{ }}$$
Work Step by Step
$$\eqalign{
& {\text{The slope is undefined.}}{\text{Then the equation of the line is in the}} \cr
& {\text{form }}x = {x_1}\left( {{\text{vertical line}}} \right),{\text{ that passes through the point }}\left( {{x_1},{y_1}} \right). \cr
& {\text{The given point is }}\underbrace {\left( {0,5} \right)}_{\left( {{x_1},{y_1}} \right).} \cr
& {\text{Therefore}}{\text{,}} \cr
& x = 0{\text{ }}\left( {y{\text{ - axis}}} \right) \cr} $$
