\"\"

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The expression is \"\"

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\"\"                  (Substitute: a = 4 and b = 9)

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\"\"                    (Multiply: \"\")\"\"

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First find the value of \"\"

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The radical \"\" indicates positive square roots of 6.

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\"\"                       (Factorize: \"\")

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= 6                             (Recall: \"\")\"\"

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The value of the expression is 6.