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 slope = -1/3
slope intercept form of line with given point and slope = -1/3
y = -1/3 x + b
-2 = -1/3(-7) + b
-6/3 -7/3 = b
-13/3 = b
y = -1/3 x -13/3 mutiply through by 3
3y = -x -13 re-arrange
3y+x = - 13 need 3 on the right side .... multiply through by - 3/13
-9/13 y - 3/13 x = 3 you can take it from here !