$\"\"$

\

Substitute $\"\"$ in slope formula.

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$\"\"$

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$\"\"$

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Multiply each side by negative (r + 2).

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$\"\"$

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$\"\"$ $\"\"$

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Multiply each side by negative 2.

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$\"\"$

\

$\"\"$

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Subtract 2 from each side.

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$\"\"$

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$\"\"$ \ \ $\"\"$

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The value of r is 6.