$\"\"$

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The system of equations are $\"\"$ and $\"\"$ .

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$\"\"$ Equation (1)

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$\"\"$ Equation (2)

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Solve the second equation for b.

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Apply subtraction property of equality: Subtract 9a from each side.

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$\"\"$

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Rearrange the terms using commutative property of addition: a + b = b + a.

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$\"\"$

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

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

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Apply division property of equality: Divide each side by 3.

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$\"\"$

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$\"\"$ (Cancel common terms) $\"\"$

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

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$\"\"$

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Distribute terms using distributive property: a( b $\"\"$ c ) = ab $\"\"$ ac.

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$\"\"$

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

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$\"\"$ (Add: $\"\"$ ) $\"\"$ $\"\"$ (Subtract 80 from each side)

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

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

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

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Apply division property of equality: Divide each side by 11.

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$\"\"$

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$\"\"$ (Cancel common terms) $\"\"$

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Now, find the b value by substituting $\"\"$ in $\"\"$ .

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$\"\"$

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

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

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The system of solution is $\"\"$ .