+67 Find the value of B-A if the graph of Bx+Ay=3 passes through the point (-7,2), and is parallel to the graph of x + 3y = -5.
+36915 x + 3y = -5. re-arrange
y = - 1/3 x - 5 slope = - 1/3 parallel slope is the same -1/3
y = - 1/3 x + b sub in the given point to calculate 'b'
2 = - 1/3 (-7) + b so b = -1/3
y = -1/3 x - 1/3 multiply by 3 to get rid of the fraction
3y = -x -1
x + 3y = -1
-3x-9y= 3 you can finish 
