\"\"

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Original function is \"\"

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Replace x = 4 in original function.

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\"\"

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\"\"                               (Subtract: \"\")\"\"

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Replace x = – 2 in original function.

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\"\"

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\"\"                          (Product of two same signs is positive)

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\"\"                                (Add: \"\")                   \"\"

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\"\" and  \"\".

\