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Question
If `x + 1/x = 4, "then" x^3 + 1/x^3 =` ______.
Options
52
76
64
62
MCQ
Fill in the Blanks
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Solution
If `x + 1/x = 4, "then" x^3 + 1/x^3 =` 52.
Explanation:
`x^3 + 1/x^3 = (x + 1/x)^3 - 3(x + 1/x)`
`x^3 + 1/x^3 = (4)^3 - 3(4)`
`x^3 + 1/x^3 = 64 - 12`
`x^3 + 1/x^3 = 52`
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