$\"\"$

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The function is $\"\"$

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$\"\"$ ( $\"\"$ )

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$\"\"$

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$\"\"$ (Substitute x and y)

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$\"\"$

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The slope is $\"\"$

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The point-slope form is $\"\"$

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$

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$\"\"$ (Subtract 4 from each side)

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$\"\"$

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

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$\"\"$

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$\"\"$

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Therefore the tangent line equation is $\"\"$ .