Giúp mình câu k câu o

k)

 `(x+1)^12`  `=` `(x+1)^14`

  `=>`  `(x+1)^14` `-` `(x+1)^12` `=` 0

`<=>`  `(x+1)^12` `.` `((x+1)^2 - 1)` `=` 0

 `<=>` $\left[\begin{matrix} (x+1)^{12}=0\\ ((x+1)^2 - 1)=0\end{matrix}\right.$

 `<=>` $\left[\begin{matrix} x=-1\\ x=0\\ x=-2\end{matrix}\right.$

o)

 `5^(x+3)` `+` `5/6`.`5^(x+4)` `=`  `275/2`

 `5^(x+3)` . `(1+ 5/6 . 5)`  `=` `275/2`

   `=>` `5^(x+3)` . `31/6` `=` `275/2`

   `=>` `5^(x+3)`  `=` `825/31`

   `=>` `5^x` `.` `5^3` `=` `825/31`

   `=>`  `5^x` `=` `33/155`

   `=>`  `x` $\approx$ `-0,96`  ( `\log_5` `33/31` )