两题数学题帮帮解答.

来源：百度知道 编辑：UC知道 时间：2024/05/28 11:23:58
已知A=2B，C=5A（A不等于0），求代数A-4B+C分之6A+2B-C的值

某影剧院有20排座位，已知第一排有18个座位，后一排比前一排多2个座位，写出第n排的座位数An的公式，并求出第19排的座位数。

1. C=10B,A=2B, 2B-4B+1.2B+2B-6B= -4.8B。
2.第一排有16+2*1,第二排有16+2*2，第n排有16+2*n，16+2*19＝54

C=5A=5(2B)=10B
(6A+2B-C)/(A-4B+C)=[6(2B)+2B-10B]/[2B-4B+10B]=4B/8B=1/2

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类似！

2/1

16+2N 54