Đáp án+Giải thích các bước giải:
`1)sqrt{(4+sqrt2)^2}=|4+sqrt2|=4+sqrt2` $\\$ `2)sqrt{(3-sqrt3)^2}=|3-sqrt3|=3-sqrt3` $\\$ `3)sqrt{(4-sqrt{17})^2}=|4-sqrt{17}|=\sqrt{17}-4` $\\$ `4)2sqrt3+sqrt{(2-sqrt3)^2}=2sqrt3+|2-sqrt3|=2sqrt3+2-sqrt3=sqrt3+2` $\\$ `5)sqrt{4-2sqrt3}-sqrt3=sqrt{3-2sqrt3+1}-sqrt3=sqrt{(sqrt3-1)^2}-sqrt3=sqrt3-1-sqrt3=-1` $\\$ `6)sqrt{11+6sqrt2}-3+sqrt2=sqrt{9+2.3.sqrt2+2}-3+sqrt2=sqrt{(3+sqrt2)^2}-3+sqrt2=3+sqrt2-3+sqrt2=2sqrt2` $\\$ `7)sqrt{9x^2}-2x(x<0)=sqrt{(3x)^2}-2x=|3x|-2x=-3x-2x(do \ x<0)=-5x` $\\$ `8)A=x-4+sqrt{x^2-8x+16}=x-4+sqrt{(x-4)^2}=x-4+|x-4|`
Với `x>=4=>|x-4|=x-4=>A=x-4+x-4=2x-8`
Với `x<=4=>|x-4|=4-x=>A=x-4+4-x=0`
