$\"\"$

Slope of the two non vertical lines is $\"\"$ .

The y-coordinate are same. So, the line is y = $\"\"$ 3. The line is horizontal line.

So, slope is zero. $\"\"$

Check the solution by substituting the values.

Replace $\"\"$ in slope formula.

$\"\"$

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

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

The slope is zero.