Both slopes are going to be the same, as parallel lines have the same slopes but different y-intercepts. To find the slope of this line (if you haven’t already), you need to isolate y.
4x - 5y= -1
-5y= -4x - 1 (or -1 - 4x)
-y= (-4/-5)x - 1/5
Canceling out the negatives,
y= (4/5)x + 1/5.
Therefore, the slope of both the listed line and any line parallel to it is 4/5.