※ 引述《nokol (騷人墨客)》之銘言：
: http://i.imgur.com/Iea9TWO.jpg
: 想請教大師指點方向
: 感激不盡，謝謝你，謝謝
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: Sent from JPTT on my Samsung SM-G955F.
A = 3^x - 9
B = 9^x - 3
(A + B)[A^2 + B^2 - AB - (A + B)^2] = 0
=> [A + B][-3]AB = 0
=> x = 2, 1/2, 1
=> 實根和 = 7/2
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