2 câu trả lời
`#tnvt`
`\frac{3\sqrt{x}}{\sqrt{x}+2}(x>=0)`
`=\frac{3\sqrt{x}+6-6}{\sqrt{x}+2}`
`=\frac{3(\sqrt{x}+2)-6}{\sqrt{x}+2]`
`=3-\frac{6}{\sqrt{x}+2}`
Vì `\sqrt{x}+2>=2`
`=>\frac{6}{\sqrt{x}+2}<=6/2=3`
`=>3-\frac{6}{\sqrt{x}+2}>=3-3=0`
Dấu `=` xảy ra khi `\sqrt{x}+2=0<=>x=0`
Vậy `GTNNNN=0` khi `x=0`