VĂ ROG!! URGENT!
[tex]a)( \frac{2}{ \sqrt{7} } )^{ - 3} [/tex]
[tex]b)( \sqrt{5} ) ^{ - 2} [/tex]
[tex]c)( \frac{2}{5} ) {}^{3} \div ( \frac{2}{5} ) ^{ - 3} [/tex]
[tex]d)( \sqrt{ \frac{5}{6} } \times \sqrt{2} [/tex])
​