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Slope of the line

The slope of a non-vertical line through any two points is given by

$\"\"$

Substitute $\"\"$ in slope formula.

$\"\"$

$\"\"$ (Signs are same. So, product is positive)

$\"\"$ (Subtract: $\"\"$ )

$\"\"$ (Add: $\"\"$ )

$\"\"$ (Divide: $\"\"$ )

Since division by zero is undefined, the slope is undefined.

$\"\"$

The slope m of the line that passes through the pair of points is undefined.