Answer:
Those points are 
units apart.
You can use this one app it’s called Cymath it’s really helpful with these types of problems,
For the first one it’s 40 feet
The second one is 32
The last is 40
If we rewrite it as y=mx+d (which can be taken from here from subtracting ax and c from both sides, then dividing b, resulting in y=(-a/b)(x)-c/b. We can then substitute -a/b for m and -c/b for d), if d=0, then we have m as a constant and as we add a specific number to y (that number being m) every time the x value increases by 1, it therefore forms a straight line. If d is not 0, then we simply add d to every single number - this is still a straight line due to that we still add a specific number to y every time x increases by 1 every single time
The third one is the answer
