The expression is .

                (Replace x = 9, y = 4 and z =12)

 To simplify the expression follow the order of operations: (PEMDAS)

1.     Evaluate the expressions inside Brackets/Parenthesis (P).

2.     Evaluate Powers/Exponents (E).

3.     Multiply and/or Divide in order from left to right (MD).

4.     Add and/or Subtract in order from left to right (AS).

A simple technique for remembering the order pf operations is turned into phrase

“Please Excuse My Dear Aunty Sally”

According order of operations inside the grouping symbols should be

evaluated first.

First operation is multiply the values inside the parenthesis.

        (Multiply: )

             (Multiply: )

                          (Subtract: )

Next operation is multiplication.

                              (Multiply:)

Next operation is addition.

                                       (Add: )

The value of the expression is .