$\"\"$

\

The equation is $\"\"$ .

\

Apply division property of equality: Divide each side by 5.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Case:1 a = b.

\

$\"\"$

\

Multiply each side by 5.

\

$\"\"$

\

$\"\"$

\

Apply distributive property: a( b + c) = ab + ac.

\

$\"\"$

\

$\"\"$

\

Subtract k from each side.

\

$\"\"$

\

$\"\"$

\

Add 20 to each side.

\

$\"\"$

\

$\"\"$

\

Divide each side by 4.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Case:2 a = $\"\"$ b.

\

$\"\"$

\

Multiply each side by 5.

\

$\"\"$

\

$\"\"$

\

Apply distributive property: a( b + c) = ab + ac.

\

$\"\"$

\

$\"\"$

\

Add k to each side.

\

$\"\"$

\

$\"\"$

\

Add 20 to each side.

\

$\"\"$

\

$\"\"$

\

Divide each side by 6.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Check:

\

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

\

$\"\"$

\

$\"\"$

\

The absolute value of $\"\"$ is 3.

\

$\"\"$

\

$\"\"$

\

The equality is true. $\"\"$

\

Check:

\

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

\

$\"\"$

\

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

\

$\"\"$

\

The equality is true.

\

$\"\"$

\

The solution set is $\"\"$ .