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Question
Find : `"a"^3+1/"a"^3`, if `"a" +1/"a"=5`.
Sum
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Solution
`"a" +1/"a"=5`
`⇒("a"+1/"a")^3=(5)^3`
`⇒"a"^3+1/"a"^3+3"a"xx1/"a"("a"+1/"a")=125`
`⇒"a"^3+1/"a"^3+3(5)=125` ........`["a"+1/"a"=5]`
`⇒"a"^3+1/"a"^3+15=125`
`⇒"a"^3+1/"a"^3=125-15`
`⇒"a"^3+1/"a"^3=110`
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