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Question
If `x - 1/x = 5, "then" x^3 - 1/x^3 =` ______.
Options
110
140
125
127
MCQ
Fill in the Blanks
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Solution
If `x-1/x=5, "then" x^3-1/x^3=` 140.
Explanation:
`x^3-1/x^3=(x-1/x)^3+3(x-1/x)`
`x^3-1/x^3=(5)^3+3(5)`
`x^3-1/x^3=125+15`
`x^3-1/x^3=140`
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