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

\

The equation is $\"\"$ .

\

Write two cases:

\

Case-1: $\"\"$

\

$\"\"$

\

Case-2: $\"\"$

\

$\"\"$

\

$\"\"$

\

Solve the equation for Case-1.

\

$\"\"$

\

Apply addition property of equality: Add 9 to each side.

\

$\"\"$

\

$\"\"$ (Apply Additive inverse property: $\"\"$ )

\

$\"\"$ (Apply Additive identity property: $\"\"$ )

\

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

\

Check:

\

To check the solution, substitute $\"\"$ in original equation.

\

$\"\"$

\

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

\

The absolute value of 20 is 20.

\

$\"\"$

\

Compare the values the equation is true. $\"\"$ is a solution.

\

$\"\"$

\

Solve the equation for Case-2.

\

$\"\"$

\

Apply addition property of equality: Add 9 to each side.

\

$\"\"$

\

$\"\"$ (Apply Additive inverse property: $\"\"$ )

\

$\"\"$ (Apply Additive identity property: $\"\"$ )

\

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

\

$\"\"$

\

Check:

\

To check the solution, substitute $\"\"$ in original equation.

\

$\"\"$

\

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

\

$\"\"$ (The absolute value of $\"\"$ )

\

Compare the values the equation is true. $\"\"$ is a solution. $\"\"$

\

The solution set is $\"\"$ .