Question 959140
the equation of the line that passes through ({{{1}}}, {{{9}}}) and  perpendicular to {{{x = 5}}} (vertical line) is {{{y=9}}} (horizontal line)

{{{drawing( 600, 600, -10, 10, -10, 15,circle(1,9,.12),locate(1,9,p(1,9)),locate(-5.2,9.7,y=9),locate(4.5,5,x=5),line(5,-10,5,10), graph( 600, 600, -10, 10, -10, 15, 9,9)) }}}