Răspuns:
[tex] \frac{7}{ \sqrt{2} } = \frac{7 \times \sqrt{2} }{ \sqrt{2} \times \sqrt{2} } = \frac{7 \sqrt{2} }{2} [/tex]
[tex] \frac{ - 13}{ \sqrt{13} } = \frac{ - 13 \times \sqrt{13} }{ \sqrt{13} \times \sqrt{13} } = - \frac{13 \sqrt{13} }{13} = - \sqrt{13} [/tex]
[tex] \frac{5 \sqrt{72} }{6 \sqrt{30} } = \frac{5 \sqrt{12} }{6 \sqrt{5} } = \frac{10 \sqrt{3} }{6 \sqrt{5} } = \frac{5 \sqrt{3} }{3 \sqrt{5} } = \frac{5 \sqrt{3} \times \sqrt{5} }{3 \sqrt{5} \times \sqrt{5} } = \frac{5 \sqrt{15} }{15} = \frac{ \sqrt{15} }{3} [/tex]
