The equation of line AB is y = 1 over3x - 1. write a equation of a line perpendicular line AB in slope-intercept form that contains point (4, -2).

PLEASE HELP ASAP THANK YOU!!!

And I need to also know HOW you got the answer. Thanks so much. (:

Respuesta :

y =1/3x - 1 so slope = 1/3
if perpendicular, slope = -3

passing thru (4,-2) then
y = mx +b
-2=-3(-2) + b
-2=6+b
-2-6 = b 
so b = -8

equation:
y = -3x - 8