What exactly are you asking?
Well... One way you can do this is by testing a set of arrays and see the trend. If I chose to find what y1 is in (100, y1) and what y2 is in (101, y2), I would find the difference between y2 and y1. If y2 - y1 is positive, this means there is a positive relationship and y is also approaching POSITIVE infinity. A negative relation means that it is approaching NEGATIVE infinity. However, it could be approaching a single number like "4" for instance, and you just need to plug in the right number of data sets to make that educated guess.
Formula Example:
5 + 1 / (x + 1) will always approach 5 because "1 / (x + 1) will approach 0".
Hope this helps.
Given:
The given equation of line is

To find:
The equation of line that passes through (-5,4) and is parallel to the given line.
Solution:
Slope intercept form of a line is
...(i)
where, m is slope and b is y-intercept.
We have,
...(ii)
On comparing (i) and (ii), we get

Slope of given line is
.
Slope of parallel lines are same. So, slope of parallel line is
.
The required line passes through (-5,4) with slope
. So, the equation of line is




Adding 4 on both sides, we get



Therefore, the correct option is a.