$\"\"$

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The marginal cost is $\"\"$ .

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Then the anti derivative of $\"\"$ is

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$\"\"$

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$\"\"$ , where $\"\"$ is a constant.

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The cost of producing one item is $ $\"\"$ .

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

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$\"\"$

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

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$\"\"$ .

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$\"\"$

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Find the cost of producing $\"\"$ items.

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

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$\"\"$

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Therefore the cost of producing $\"\"$ items is $ $\"\"$ .

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$\"\"$

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The cost of producing $\"\"$ items is $ $\"\"$ .