Răspuns:
[tex] - \frac{24}{ \sqrt{72} } = - \frac{24}{6 \sqrt{2} } = - \frac{4}{ \sqrt{2} } = - \frac{4 \sqrt{2} }{2} = - 2 \sqrt{2} [/tex]
[tex] - \frac{21}{ \sqrt{63} } = - \frac{21}{3 \sqrt{7} } = - \frac{7}{ \sqrt{7} } = - \frac{7 \sqrt{7} }{7} = - \sqrt{7} [/tex]
[tex] \frac{42}{ \sqrt{126} } = \frac{42}{3 \sqrt{14} } = \frac{14}{ \sqrt{14} } = \frac{14 \sqrt{14} }{14} = \sqrt{14} [/tex]
[tex] \frac{52}{4 \sqrt{52} } = \frac{13}{ \sqrt{52} } = \frac{13}{2 \sqrt{13} } = \frac{13 \sqrt{13} }{26} = \frac{ \sqrt{13} }{2} [/tex]
