※ 引述《SC333 (SC)》之銘言:
: (2x + 14)^1/3 - (2x - 14)^1/3 = 4^1/3
: 共有多少個實根?
4 = 28 - 3 * [4^(1/3)] * [4x^2 - 196]^(1/3)
=> [4x^2 - 196]^(1/3) = 2^(7/3)
=> 4x^2 = 324
=> x = +- 9
2個實根
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