\"\"\"\"\"\"

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The equation is \"\".

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\"\"                   (Apply Distributive property: \"\")

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

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According to addition property of equality: Add 21 to each side.

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\"\"

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\"\"                          (Apply additive inverse property: \"\")

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\"\"                          (Apply additive identity property: \"\")

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

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According to division property of equality: Divide each side by 7.

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\"\"

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\"\"                                 (Cancel common terms)

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

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

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

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Compare the values, the equation is true.\"\"

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The value of \"\".