$\"\"$

\

The proportion is $\"\"$ .

\

Apply cross products property: If $\"\"$ where $\"\"$ then $\"\"$ .

\

$\"\"$

\

$\"\"$

\

Subtract 9n from each side.

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

Divide each side by negative 4.

\

$\"\"$

\

Cancel common terms.

\

$\"\"$ . $\"\"$

\

To check the solution, substitute the value of $\"\"$ in the proportion $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Cancel common terms.

\

$\"\"$ . $\"\"$

\

The value of $\"\"$ .