\"\"

\

The expression is \"\".

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\"\"               (Substitute x = 7.1,  y = 2.5)

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\"\"         (Apply assositative property: a + (b + c) = (a + b) + c)

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\"\"                 (Subtract: \"\")

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\"\"                                (Add: \"\")\"\"

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The value of expression is 1.8.