Đáp án+Giải thích các bước giải:
`a)\sqrt{27x^2}(x>=0)`
`=\sqrt{9.3.x^2}`
`=|3\sqrt{3}x|`
`=3\sqrt{3}x(x>=0)`
`b)\sqrt{8xy^2}(x>=0,y<=0)`
`=\sqrt{4.2x.y^2}`
`=|2\sqrt{2x}y|`
`=-2\sqrt{2x}y(x>=0,y<=0)`
`c\sqrt{25x^3}(x>0)`
`=\sqrt{(5x)^{2}.x}(x>0)`
`=|5x\sqrt{x}|`
`=5x\sqrt{x}(x>0)`
`d)\sqrt{48xy^4}(x>=0,y \in RR)`
`=\sqrt{16.3x.(y^2)^2}`
`=|4y^2\sqrt{3x}`
`=4y^2\sqrt{3x}(x>=0,y^2>=0AAy \in RR)`
