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

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The equations are $\"\"$ .

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$\"\"$ Equation (1)

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$\"\"$ Equation (2)

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Solve the first equation $\"\"$ .

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According to addition property of equality: Add 3y to each side.

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$\"\"$

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

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

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

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Substitute $\"\"$ in equation (2).

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$\"\"$

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

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

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According to division property of equality: Divide each side by 10.

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$\"\"$

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$\"\"$ (Cancel common terms)

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

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Substitute $\"\"$ in equation $\"\"$ .

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$\"\"$

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

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The solution is $\"\"$ .