+25 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.
IT ISN'T 2
+23252 Every line that is parallel to the line x + 3y = -5 has the form x + 3y = k
where diffierent values of k will give you different (but parallel) lines.
Placing the point (-7, 2) into x + 3y = k ---> (-7) + 3(2) = -7 + 6 = -1 ---> k = -1.
So, the equation of the line that passes through (-7, 2) that is parallel to x + 3y = -5
is x + 3y = -1.
To get this equation to have the form Ax + By = 3
instead of x + 3y = -1
we'll need to multiply the bottom equation by -3:
-3 [ x + 3y = -1 ] ---> -3x + -9y = 3
This makes A = -3 and B = -9.
