Question 978003
given: 

find the line passing through ({{{2}}},{{{2}}}) and perpendicular to {{{x=-9}}}

The line {{{x=-9}}} is a {{{vertical}}} line. Because it is vertical, its slope {{{m}}} is {{{undefined}}}.

Since we have a vertical line of {{{x=-9}}}, we need something {{{perpendicular}}} to it (a horizontal line) passing through ({{{2}}},{{{2}}}). so, we can use {{{y=2}}};it a horizontal line and is perpendicular to the vertical line, and it runs through the point ({{{2}}},{{{2}}})


{{{drawing( 600, 600, -15, 15, -10, 10,
line(-9,10,-9,-10), circle(2,2,.12),locate(2,2,p(2,2)),
 graph( 600, 600, -15, 15, -10, 10, 2,2)) }}}