You can put this solution on YOUR website!
Undefined slope means that the slope is dividing by zero. So there is no 'run'. It is a straight up and down, vertical line. If it passes through (-8,1) then the line must be x = -8.
A line parallel to x = 8 would also have an undefined slope, meaning it is a vertical line. If it passes through the point (-3,0) then it must be x=-3. It's a vertical line at x=-3.
Lastly, if a line passes through (-4,2) and (1,-5). First find the slope:
m = (y2-y1) / (x2-x1)
m = (-5 - 2) / (1 - -4)
m = -7 / (1+4)
m = -7 / 5
Now put this value for m into y=mx+b, and use either point, (-4,2) or (1,-5) to solve for b:
-5 =(-7/5)(1) + b
-5 + 7/5 = b
b = -18/5
The equation of the line is thus y = (-7/5)x -18/5
Hope this helps! Let me know if you're confused by anything I wrote.