急救!!! 若(C-B):(B-A)=2:1,(B+A):(B:C)=5:6 求A:B:C。
*如果答得完整,有解釋,清楚,將會選為最佳回答。(10分)?
回答 (1)
(C-B):(B-A) = 2:1 就是 (C-B)/(B-A) = 2/1 = 2,
則 C-B = 2(B-A), 整理得 2A-3B+C = 0
"(B+A):(B:C)" 疑是 "(B+A):(B+C)" 之誤植?
(B+A):(B+C) = 5:6 相當於 (B+A)/(B+C) = 5/6,
則 6(B+A) = 5(B+C), 整理得 6A+B-5C = 0
聯立兩方程式, 以 C 表示 A, B 之解得:
A = (7/10)C, B = (8/10)C
即 A:C = 7:10, B:C = 8:10
故 A:B:C = 7:8:10
收錄日期: 2021-04-26 12:16:02
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