The expression is.

Substitute value of x = 3 and y = 4.

Then the expression is  

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”

First operation is evaluating the expression with in parenthesis.

                                      (Subtract:   )

Next operation is squaring

                                              (Squaring:   )

Next operation is multipling

                                                 (Multiply:  )

Next operation is Subtraction.

                                                   (Subtract: ).

The value of given expression is -17.