The expression is .

          (Substitute x = 7.1,  y = –2.5)

                     (Product of two same signs is positive)

                            (Subtract: )

\

To subtract -5.2 means add 5.2

                                   (Product of two same signs is positive)

                                             (Add: 2.5 + 5.2 = 7.7) \ \

The value of expression is 7.7.