Răspuns:
[tex]( \frac{3}{4 } \times \sqrt{21} ) \div ( \frac{6}{5} \times \sqrt{7} ) \\ \frac{3 \sqrt{21} }{4} \div \frac{6 \sqrt{7} }{5} \\ \frac{3 \sqrt{21} }{4 } \times \frac{5}{6 \sqrt{7} } \\ \frac{ \sqrt{3} }{4} \times \frac{5}{2} \\ \frac{5 \sqrt{3} }{8} [/tex]
