Question 22570
Remember, in perpendicular lines, the slope is the neg, reciprocal of the slope of the first line.  In this case the slope of the first line is 3 so its negative reciprocal is -1/3.  use this number as your slope for the perpendicular line.
now put that in the following formula
y-y1=m(x-x1)
If you are wondering about the 1's in the equation they indicate the first set of points you have.  If you had 2 sets of points, then you would know which set to use.

for your problem put the points in and the slope (m) so...

y-(-3)=-1/3(x-6)   following me?
y+3=-1/3x+2
y=-1/3x+2-3
y=-1/3x-1

do you see how I got the answer?