$\"\"$

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The functions are $\"\"$ .

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a) (f + g)(x)

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$\"open$

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

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$\"\"$

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$\"\"$ .

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$\"\"$

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b) (f $\"\"$ g)(x)

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$\"open$

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

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$\"\"$

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Product of same sings is positive.

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$\"\"$

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$\"\"$ .

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$\"\"$

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c) $\"open$

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$\"\"$

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

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$\"\"$ (Using FOIL method)

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$\"\"$

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

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d) $\"open$

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$\"open$

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$\"\"$ , $\"\"$ (Substitute $\"\"$ ). $\"\"$

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The functions are $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ .