Question 831863
Slopes are the same if parallel.

y=-3x+b and you have the point which this line must contain.  Plug in the values after solving for b.  


b=y-(-3x)
b=y+3x
b=4+3*1
b=7
-
Your target equation is y=-3x+7.


Now adjust to form, as Ax+By=C.