$\sqrt{x+1}+$ $5\sqrt{4x+4}-$ $\sqrt{25x+25}=24$

`\sqrt{x+1}+5\sqrt{4x+4}-\sqrt{25x+25}=24`   ĐKXĐ: `x\geq-1`

`<=>\sqrt{x+1}+5\sqrt{4(x+1)}-\sqrt{25(x+1)}=24`

`<=>\sqrt{x+1}+10\sqrt{x+1}-5\sqrt{x+1}=24`

`<=>6\sqrt{x+1}=24`

`<=>\sqrt{x+1}=4`

`<=>(\sqrt{x+1})^2=4^2`

`<=>x+1=16`

`<=>x=15`  `(TMĐK)`

Vậy `x=15`.