$\"\"$

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Guassian elimination method :

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System of equations are

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$\"\"$

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Solve the equations $\"\"$ for $\"\"$ .

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$\"\"$

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

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

\

$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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

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$\"\"$ .

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$\"\"$ .

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$\"\"$ and $\"\"$ .

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$\"\"$

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$\"\"$ .