Algebra-1

To find out which pair of points would yield a line with an undefined slope, we need to recall the formula for calculating the slope between two points  and , which is .

A line has an undefined slope when the denominator of this formula, , is equal to . That means the -coordinates of the two points must be the same.

Let's check each pair of points:

A:  and

For these points, , , , and .

The slope .

Here, the slope is  since the change in  is  while the change in  is not .

B:  and

Here, , , , and .

The slope

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