指數方程問題

2007-04-17 1:37 am
1. 9(3^x+1)=27^2x
2. 2^(x+2)+2^x=10

回答 (2)

2007-04-17 1:40 am
✔ 最佳答案
1.
9(3^x+1)=27^2x
3^2 (3^x + 1) = (3 ^ 3) ^ 2x
3^2x + 9 = 3 ^ 6x
3 ^ 4x = 9
3^ 4x = 3 ^ 2
4x = 2
x = 1 / 2


2.
2^(x+2)+2^x=10
2 ^x (4 + 1) = 10
2^ x (5) = 10
2^x = 2
x = 1

2007-04-17 2:21 am
1.

9(3^x+1)=27^2x

3^2 (3^x + 1) = (3 ^ 3) ^ 2x

3^2x + 9 = 3 ^ 6x

3 ^ 4x = 9

3^ 4x = 3 ^ 2

4x = 2

x = 1 / 2





2.

2^(x+2)+2^x=10

2 ^x (4 + 1) = 10

2^ x (5) = 10

2^x = 2

x = 1
參考: me


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