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.

B - A = 2

Step-by-step explanation:

Recall that parallel lines have the same slope.  Thus, line Ax + By = 3, parallel to x + 3y = -5, has the form x + 3y = C.  This latter line passes through the point (-7, 2), and so             -7 + 3(2) = C must be true.  Then -7 + 6 = C, and C = -1.  

In both equations A = 1 and B = 3.  Thus, B - A = 3 - 1, or B - A = 2

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step-by-step explanation: