`x=2^(1/3)-2^(-1/3)` then find `2x^3+6x` – InterviewSolution

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1.	`x=2^(1/3)-2^(-1/3)` then find `2x^3+6x`
Answer» `x=2^(1/3)-2^(-1/3)` `2x^3+6x=2(2^(1/3)-2^(-1/3))^3+6(2^(1/3)-2^(-1/3))` `=2(2-2^(-1)-3(2^(1/3)-2^(-1/3)))+6(2^(1/3)-2^(-1/3))` `=4-1-6(2^(1/3)-2^(-1/3))+6(2^(1/3)-2^(-1/3))` `=3`.

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