$\"slope$ $\"\"$

Substitute $\"\"$ in slope formula.

$\"\"$

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

$\"\"$

$\"\"$ (Multiply each side by 3)

$\"\"$

$\"\"$ (Add 3 to each side)

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

$\"\"$ (Multiply each side by negative one) $\"\"$

The value of r is $\"\"$ .