1,
`a) \sqrt{-22x}`
ĐK: `-22x>=0 <=> x<=0`
Vậy `x<=0`
`b) sqrt{6-x}`
ĐK: `6-x>=0<=>x<=6`
Vậy `x<=6`
`c) \sqrt{-8+x}`
ĐK: `-8+x>=0<=>x>=8`
Vậy `x>=8`
`d) \sqrt{2x+1}`
ĐK: `2x+1>=0<=>x>=-1/2`
Vậy `x>=-1/2`
`e) sqrt{4-2x}`
ĐK: `4-2x>=0<=>2x<=4<=>x<=2`
Vậy `x<=2`
`j) \sqrt{11x}`
ĐK: `11x>=0<=>x>=0`
Vậy `x>=0`
`g) \sqrt{4x-12}`
ĐK: `4x-12>=0<=>4x>=12<=>x>=3`
Vậy `x>=3`
`i) \sqrt{3x+12}`
ĐK: `3x+12>=0<=>3x>=-12<=>x>=-4`
Vậy `x>=-4`
`k) sqrt{8-4x}`
ĐK: `8-4x>=0<=>4x<=8<=>x<=2`
Vậy `x<=2`
`2,`
`a) \sqrt{(3+\sqrt{5})^2}`
`=|3+\sqrt{5}|`
`=3+\sqrt{5}`
`b) \sqrt{(3-\sqrt{5})^2}`
`=|3-\sqrt{5}|`
`=3-\sqrt{5}`
`c) \sqrt{(3-\sqrt{10})^2}`
`=|3-\sqrt{10}|`
`=\sqrt{10}-3`