Simple point - slope question

[springs015]

Pretty simple question, I feel dumb for not know it.

say you have a point (-1,0) and a equation of a line y = -3

the goal is to write the equation of the line (in slope - intercept) that runs (a) parallel to the give line (b) and perpendicular to the give line .

I got (a). y =0

and I am pretty sure (b) is x = -1

My problem is I don't understand how you get (b) using point- slope

this is how I see it, y - 0 = undefined(x +1)

 

[skeeter]

the point-slope form only works for defined slopes ... all vertical lines have undefined slope and will always be of the form x = some constant