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Question
Evaluate: `(2"a"+1/"2a")(2"a"-1/"2a")`
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Solution
`(2"a"+1/"2a")(2"a"-1/"2a")`
`=(2"a")^2-(1/"2a")^2` ......[ ∵ (a − b) (a + b) = a2b2]
`=4"a"^2-1/"4a"^2`
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