The line of the equation x=3 is a vertical line with a constant x-value.
The lines that are perpendicular to vertical lines are horizontal lines. So, you have to find the equation for a horizontal line that passes through the point (2,-5) and crosses the line x=3.
Horizontal lines have the same value of y, regardless of the value of x. Knowing one point of this line allows you to determine the equation since the y-coordinate of the said point will be equal to the equation of the horizontal line. In this case, the y-coordinate of the point is -5, which means that the equation of the horizontal line is:
