Final answer:
The slope of the line passing through the given points is undefined.
Step-by-step explanation:
To find the slope of a line passing through two given points, we can use the formula m = (y2 - y1) / (x2 - x1).
Using the points (4,2) and (4,3), we have:
m = (3 - 2) / (4 - 4)
m = 1 / 0
Since division by zero is undefined, the slope of the line passing through these points is undefined.