$\"\"$

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The expression is $\"\"$ .

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$\"\"$ (Replace a with 2, b with -3/4)

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$\"\"$ (Multiply: $\"\"$ )

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$\"\"$ (Divide: $\"\"$ )

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$\"\"$

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$\"\"$ (Subtract: $\"\"$ ) \ \

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$\"\"$

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The value is $\"\"$ .