So you want to isolate the y first, you would get 5y= x+40 . Then divide by 5 to get y without a coefficient
y=x/5 +8
So parallel lines always have the same slope
y =1/5x + ?
You have values for x and y so plug it in
9 = 1/5 (-5) +?
9 = ?-1
?= 10
So your equation is y=1/5x +10