Answer:
-6
Step-by-step explanation:
The parallel line can be written using the same x- and y-coefficients, but with a different constant:
x +3y = constant
For the line to go through the given point, the constant must be ...
(-7) +3(2) = constant
-1 = constant
In order for the constant to be +3 instead of -1, the entire equation must be multiplied by -3:
-3x -9y = 3 ⇒ A = -3, B = -9
Then the expression B-A is ...
B -A = (-9) -(-3) = -6
The value of B - A is -6.
