$\"\"$

The equation $\"\"$ represents a constant rate of change and k is the

constant of variation.

Compare the equation $\"\"$ with equation $\"\"$ .

The constant of variation is $\"\"$ . $\"\"$

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

$\"\"$

$\"\"$ (Substitute $\"\"$ ) \ \

$\"\"$ (Additive indentity property: $\"\"$ )

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

Slope $\"\"$ .

$\"\"$

The slope m of the line that passes through the pair of points is $\"\"$ .