\"\"\"\"

\

The equation is \"\".

\

Write two cases:

\

Case-1: a = b.

\

\"\"

\

Case-2: \"\"

\

\"\"

\

\"\"

\

Solve the equation for Case-1.

\

\"\"

\

Apply subtraction property of equality: Subtract 9 from each side.

\

\"\"

\

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

\

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

\

Check:

\

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

\

\"\"

\

\"\"                  (Add: 12 + 9 = 21)

\

The absolute value of 21 is 21.

\

21 = 21

\

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

\

Solve the equation for Case-2.

\

\"\"

\

Apply subtraction property of equality: Subtract 9 from each side.

\

\"\"

\

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

\

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

\

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 solutions are 12 and -30.

\

The solution set is \"\".