\

The expression is 

Associative property of addition:

The way in which numbers are grouped and added does not change the sum.

For any numbers a, b and c:

Using associative property, the statement can be written as

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To simplify the expression following order of operations to performed:

1.      Evaluate the expressions inside grouping symbols.

2.      Evaluate Powers.

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

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

According order of operations inside the grouping symbols should be                                                       evaluated first.

First operation is adding the values inside the parenthesis.

                     (Add:)

The simplified expression is z + 16.