tolong dijawab ya dan diberi jln

[tex]a. \: \frac{28}{2 \sqrt{7} } = \frac{ \sqrt{7} }{ \sqrt{7} } \\ \frac{28 \sqrt{7} }{2.7} \\ \frac{28 \sqrt{7} }{14} \\ 2 \sqrt{7} [/tex]