Đáp án+Giải thích các bước giải:

 `l)(x-2/3)^{2}=5/6`

`(x-2/3)^{2}=(-\sqrt{5/6})^{2}=(\sqrt{5/6})^{2}`

`+)TH1:x-2/3=-\sqrt{5/6}`

`x-2/3=-\frac{\sqrt{30}}{6}`

`x=-\frac{\sqrt{30}}{6}+2/3`

`x=\frac{-\sqrt{30}}{6}+4/6`

`x=\frac{4-\sqrt{30}}{6}`

`+)TH2:x-2/3=\sqrt{5/6}`

`x-2/3=\frac{\sqrt{30}}{6}`

`x=\frac{\sqrt{30}}{6}+2/3`

`x=\frac{\sqrt{30}}{6}+4/6`

`x=\frac{4+\sqrt{30}}{6}`

Vậy `x\in{\frac{4-\sqrt{30}}{6};\frac{4+\sqrt{30}}{6}}.`