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 $x + 3y = -5.$
+600 The parallel condition implies that it has slope $-\frac{1}{3}$. What can you determine about $A$ and $B$ given this? Now substitute $-7A+2B=3$ with your first equation to explicitly find $A,B$ and in turn find $B-A$.
