Find the value of B - A if the graph of Ax + By = 3 passes through the point (-7,2), and is parallel to the graph of x + 3y = -5.

x + 3y = -5.      is tha same as    y = -1/3 x - 5/3     slope, m = -1/3

 

parallel line is of the form   y = -1/3 x + b

   sub in the given point      2 = -1/3 (-7)  + b     shows b = -1/3

     so line eq becomes       y = - 1/3 x -1/3

       re-arranged                  y + 1/3 x = -1/3        multiply by 3

                                                x + 3y = - 1      now you can calc  B-A