Bài 25:

`1) (1/3)^m=(1/3)^4`

`=>m=4`

`2) (-8/7)^3=(-8/7)^n`

`=>n=3`

`3) -32/(-2)^n=-32/-8=-32/(-2)^3`

`=>n=3`

`4) 8/2^n=8/4=8/2^2`

`=>n=2`

`5) (1/2)`$^{2n-1}$ `=``1/8=(1/2)^3`

`=>2n-1=3`

`=>2n=4`

`=>n=2`

`6) 1/3^2` `.` `3`$^{3n}$  `= 3^n` 

`=>`3`$^{3n-2}$  `= 3^n`

`=>3n-2=n`

`=>3n-n=2`

`=>n=2`

`=>n=1`

`7) 1/9 .3^4. 3^n=3^7`

`=>1/9 . 81 . 3^n = 3^7`

`=>9 . 3^n = 3^7`

`=>3^2 . 3^n=3^7`

`=>3`$^{2+n}$ `=3^7`

`=>2+n=7`

`=>n=5`

`8) 1/2` `.` `2`$^{n+4}$ . `2^n`  `= 2^5` 

`=>1/2 . 2^n . 2^4 . 2^n = 2^5`

`=> 1/2 . 2^4 . 2`$^{2n}$ ` = 2^5`

`=> 2^3 . 2`$^{2n}$ ` = 2^5`

`=> 2`$^{2n}$ `=2^5:2^3`

`=> 2`$^{2n}$ `=2^2`

`=>2n=2`

`=>n=1`

`9) 8^n:2^n=16^2011`

`=> (2^3)^n:2^n=(2^4)^2011`

`=>2^3n-n=2^8044`

`=>2n=8044`

`=>n=4022`

`10) 2^n + 2`$^{x+3}$ `=144`

`=>  2^x . 1 + 2^x . 2^3 = 144`

`=> 2^x . (1 + 2^3) = 144`

`=>  2^x . 9 = 144`

`=> 2^x = 144 : 9`

`=> 2^x = 16`

`=> 2^x= 2^4`

`=>x=4`

~~~~Mình không chép đề nha và nhiều câu nên hơi mất thời gian, mong bạn thông cảm~~