Đáp án:
`sqrt{8/15}=\frac{sqrt8}{sqrt15}=\frac{2sqrt2}{sqrt15}=\frac{2sqrt2sqrt15}{sqrt15sqrt15}=\frac{2sqrt30}{15}`
`sqrt{(x^3)/27}=\frac{sqrt{x^3}}{sqrt27}=\frac{xsqrtx}{3sqrt3}=\frac{xsqrtxsqrt3}{3sqrt3sqrt3}=\frac{xsqrt{3x}}{9}`
`sqrt{12/75}=sqrt{4/25}=2/5`
`5/2 sqrt{48/49}=5/2 xx\frac{sqrt48}{7}=5/2 xx \frac{4sqrt3}{7}=5xx\frac{2sqrt3}{7}=\frac{10sqrt3}{7}`