$\"\"$

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The system of equations are

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$\"\"$

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Write the equations into matrix form $\"\"$ , where $\"\"$ is coefficient matrix,

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$\"\"$ is variable matrix and $\"\"$ is constant matrix.

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$\"\"$

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Definition of inverse matrix :

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If $\"\"$ is an $\"\"$ then $\"\"$ , where $\"\"$ .

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Let $\"\"$ , then $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$ , then $\"\"$ has an inverse.

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$\"\"$

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Cofactor of $\"\"$ is

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$\"\"$

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$\"\"$

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Cofactor of $\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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Find $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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The inverse of the $\"\"$ is

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$\"\"$

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$\"\"$

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Multiply $\"\"$ by $\"\"$ to solve the system.

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$\"\"$ is

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