Answer:
undefined
Step-by-step explanation:
You want the slope of the line through points (-1, 1) and (-1, 4).
Slope
The two points lie on the vertical line x = -1. A vertical line has undefined slope.
The slope of the line is undefined.
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Additional comment
The slope is the ratio of rise to run. For a vertical line, the "run" is zero for any chosen "rise." Division by zero gives an undefined result.
