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Question
If `3"x"+1/(3"x")=3`, find : `9"x"^2+1/(9"x"^2)`
Sum
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Solution
`3"x"+1/"3x"=3`
`⇒(3"x"+1/"3x")^2=(3)^2`
`⇒(3"x")^2+(1/"3x")^2+2xx3"x"xx1/"3x"=9`
`⇒9"x"^2+1/"9x"^2+2=9`
`⇒9"x"^2+1/"9x"^2=9-2`
`⇒9"x"^2+1/"9x"^2=7`
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