Answer:
undefined
Step-by-step explanation:
To find the slope between two points, we can use the slope formula. The slope formula is:

where m is the slope and (x₁, y₁) and (x₂, y₂) are two points.
By plugging in (5, 4) and (5, 9) for (x₁, y₁) and (x₂, y₂) respectively, we get:

Note, we cannot divide by zero. By using the slope formula, we get that the slope is undefined.
I hope this helps. Happy studying.