`a) \sqrt{3x-2}=2` ĐK: `x>=2/3`
`<=> 3x-2=4`
`<=> 3x=6`
`<=> x=2`
Vậy `S={2}`
`b) \sqrt{x^2-6x+9}=x-2`
`<=> \sqrt{(x-3)^2}=x-2`
`<=> |x-3|=x-2`
`<=>`\(\left[ \begin{array}{l}x-3=x-2\\x-3=2-x\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x-x=-2+3\\x+x=2+3\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}0x=1(\text{vô lý})\\2x=5\end{array} \right.\)
`<=> x=5/2`
Vậy `S={5/2}`
`c) 5-3\sqrt{5x-1}=2|1-5x|` (1) ĐK: `x>=1/5`
Đặt `5x-1=a` (`a>=0`)
`(1)<=>5-3\sqrt{a}=2|-a|`
`<=> 5-3\sqrt{a}=2a`
`<=> 2a+3\sqrt{a}-5=0`
`<=>2a-2\sqrt{a}+5\sqrt{a}-5=0`
`<=> 2\sqrt{a}(\sqrt{a}-1)+5(\sqrt{a}-1)=0`
`<=> (\sqrt{a}-1)(2\sqrt{a}+5)=0`
`=> \sqrt{a}=1` (`2\sqrt{a}+5>0` với `AAa`)
`<=> a=1`
`=> 5x-1=1`
`<=> 5x=2`
`<=> x=2/5(\text{tm})`
Vậy `S={2/5}`