$\"\"$ $\"\"$ $\"\"$

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The equation is $\"\"$

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According to Subtraction property of equality: if a = b, then $\"\"$ .

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$\"\"$ (Subtract 3.6 from each side)

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$\"\"$ (Commutative property: a + b = b + a)

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$\"\"$ (Additive inverse property: 3.6 - 3.6 = 0)

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$\"\"$ (Additive identity property: a + 0 = a)

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$\"\"$ (Subtract: 12 - 3.6 = 8.4)

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$\"\"$

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According to division property of equality: if $\"\"$ , then $\"\"$ .

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$\"\"$ (Divide each side by 2.4)

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$\"\"$ (Cancel common terms)

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$\"\"$ (Multiply each side by negative one)

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$\"\"$ (Product of two same signs is positive)

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$\"\"$

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Check:

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To check the solution, substitute $\"\"$ in original equation.

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$\"\"$

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

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$\"\"$ (Add: 3.6 + 8.4 = 12)

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Compare the values, the equation is true. The solution is $\"\"$ .

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$\"\"$

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The value of $\"\"$ .