perpendicular lines

Thought I should post what I have so far...unsure if I am doing this right

y=-2x/3+5
y=3/2x+b
-1=3/2*1+b
-1=3/2+b
then subtract 3/2 from both sides?
-5/2=b

SO am I wrong with y=-2x/3+5 and y=2/3-5/2???

sddao:

y = -2x/3 + 5

a perpendicular line: (m=-2/3, so m_perpendicular=-(3/-2)=3/2)
y = (3/2)*x + b

sddao:

and that passes through the point (8, -20)

(x, y) = (8, -20)

[input]-20 = (3/2)*8 + b[/input]
-20 = (3/2)*8 + b |-b and +20
-b = (3/2)*8 + 20 | *-1
b = -32
perpendicular line result: y = (3/2)*x -32