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Question
If `x^2 + 1/x^2 = 23`, find the value of `x + 1/x`.
Sum
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Solution
Given: `x^2 + 1/x^2 = 23`
Step-wise calculation:
1. Recall the identity:
`(x + 1/x)^2 = x^2 + 2 + 1/x^2`
2. Substitute the known value:
`(x + 1/x)^2 = 23 + 2`
`(x + 1/x)^2 = 25`
3. Take the square root:
`x + 1/x = ±5`
Thus, the value of `x + 1/x` is either 5 or –5.
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Chapter 3: Expansions - Exercise 3B [Page 72]
