$\"\"$

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The equations are

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$\"\"$ Equation (1)

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$\"\"$ Equation (2) $\"\"$

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Rewrite the equation $\"\"$

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Subtract 0.3b from each side.

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$\"\"$

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$\"\"$ Equation (3)

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Apply CRAMER RULE.

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$\"\"$

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$\"\"$

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Evaluate each determinant.

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$\"\"$

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product of two same sings is positive.

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$\"\"$

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$\"\"$

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

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$\"\"$

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$\"\"$

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Evaluate each determinant.

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$\"\"$

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product of two same sings is positive.

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$\"\"$

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$\"\"$

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

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The solution is $\"\"$ .