(3^ -2x)-81=0

2007-03-23 3:15 am

(3^ -2x)-81=0

回答 (4)

2007-03-23 3:17 am

✔ 最佳答案

(3^ -2x)-81=0
........3^ -2x=81
........3^ -2x=3^4
............-2x=4
...............x=-2

參考: 自己。

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2007-03-23 3:19 am

3^(-2x) = 81 = 3^4

(-2x) log3 = 4 log3

-2x=4

x=-2
AS REQUIRED

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2007-03-23 3:18 am

(3^ -2x)=81

(3^ -2x)=3^4
-2x=4
-x=2
x=-2

參考: me

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2007-03-23 3:18 am

(3^ -2x)-81=0

3 ^ (-2x) = 81

3 ^ (-2x) = 3 ^ 4

-2x = 4

x = -2

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