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Question
If `"a"^2 - 7"a" + 1` = 0 and a = ≠ 0, find :
`"a"^2 + (1)/"a"^2`
Sum
Solution
`"a" + (1)/"a"` = 7
⇒ `"a"^2 + (1)/"a"^2 + 2`
= 49
⇒ `"a"^2 + (1)/"a"^2`
= 49 - 2
= 47.
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