Answer:
This problem is a trick question. The slope of the line that passes through the points (6, -5) and (6, -4) is undefined. Why? Because the line is vertical, and its equation is x = 6. To find the slope of a line, you need to use the formula (y2 - y1) / (x2 - x1), where (x1, y1) and (x2, y2) are two points on the line. But in this case, x2 and x1 are both 6, so you would be dividing by zero, which is not allowed in mathematics. So the slope does not exist, and you can write your answer as slope = undefined.