The rule to remember about generating the perpendicular family to a line is we swap the coefficients on and x and y, remembering to negate one of them. Then the constant is set directly from the intersecting point.
So we have
y = 3x + 2
-3x + 1y = 2
Swapping and negating gets the perpendiculars; the constant is as yet undetermined.
1x + 3y = constant
Since we want to go through (0,2), we could have just written
