`8)`
`ĐKXĐ`
`\sqrt(x+1)+\sqrt(5x)=\sqrt(4x-3)+\sqrt(2x+4)`
`⇔\sqrt(x+1)-\sqrt(4x-3)+\sqrt(5x)-\sqrt(2x+4)=0`
`⇔(4-3x)/(\sqrt(x+1)+\sqrt(4x-3))+(3x-4)/(\sqrt(5x)+\sqrt(2x+4))=0`
`⇔(3x-4)(1/(\sqrt(x+1)+\sqrt(4x-3))-1/(\sqrt(5x)+\sqrt(2x+4)))=0`
- Xét `1/(\sqrt(x+1)+\sqrt(4x-3))-1/(\sqrt(5x)+\sqrt(2x+4))=0`
`⇔\sqrt(x+1)+\sqrt(4x-3)=\sqrt(5x)+\sqrt(2x+4)` kết hợp đề bài dễ dàng tìm đc `x\in ∅`
`⇔x=4/3`
`10)`
`ĐKXĐ`
`\sqrt(x+\sqrt(x+1/2+\sqrt(x+1/4)))=x+3/4`
`⇔\sqrt(x+\sqrt(x+1/4+\sqrt(x+1/4)+1/4))=x+3/4`
`⇔\sqrt(x+|\sqrt(x+1/4)+1/2|)=x+3/4`
`⇔|\sqrt(x+1/4)+1/2|=x+3/4`
`⇔x-\sqrt(x+1/4)+1/4=0`
`⇔x=-1/4; 3/4`
`15)`
`ĐKXĐ`
`(x-2)(\sqrt(3x+1)-1)=3x=(\sqrt(3x+1)-1)(\sqrt(3x+1)+1)`
`⇔x-2=\sqrt(3x+1)+1∨\sqrt(3x+1)-1=0`
`⇔x=0; 8` (tự làm nhé)
