bentuk rasional [tex] \frac{21}{ \sqrt{7} } [/tex] nya brp?? tolong pake caranya

21/√7 = 21√7 / 7 = 3√7

[tex] \frac{21}{ \sqrt{7} } [/tex]
=
[tex] \frac{21}{ \sqrt{7} } \times \frac{ \sqrt{7} }{ \sqrt{7} } [/tex]
=
[tex] \frac{21 \sqrt{7} }{7} [/tex]
=
[tex] 3\sqrt{7} [/tex]