解
3^(x-1)+3^(x+1)=30
中四數學(log)
2011-03-10 6:14 am
回答 (2)
2011-03-10 6:21 am
✔ 最佳答案
3^(x - 1) + 3^(x + 1) = 303^(x - 1)[1 + 3^2] = 30
10 * 3^(x - 1) = 30
3^(x - 1) = 3
x - 1 = 1
x = 2
2011-03-14 12:54 am
3^(x-1)+3^(x+1)=30
3^(x-1) (1+3^2)=30
3^(x-1) =30 over 10
3^(x-1) =3
3^x over 3 =3
3^x =9
x=2
3^(x-1) (1+3^2)=30
3^(x-1) =30 over 10
3^(x-1) =3
3^x over 3 =3
3^x =9
x=2
參考: 自己
收錄日期: 2021-04-26 14:05:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110309000051KK01319