[tex]( \frac{2}{ \sqrt{7} } amplifici cu 2- \frac{\sqrt{7} }{2} amplifici cu \sqrt{7} :[tex] \frac{4}{2 \sqrt{7} } - \frac{ \sqrt{49} }{2 \sqrt{7} } : ( \frac{ \sqrt{7} }{3} ) ^{-3} [/tex] = [tex] \frac{4}{2 \sqrt{7} } - \frac{7}{2 \sqrt{7} } : ( \frac{ \sqrt{7} }{3} ) ^{-3} [/tex] = [tex]- \frac{3}{2 \sqrt{7} } : ( \frac{3}{ \sqrt{7} } ) ^{3} = - \frac{3}{2 \sqrt{7} } : \frac{27}{ \sqrt{343} } = - \frac{3}{2 \sqrt{7} } : \frac{27}{7 \sqrt{7} } = - \frac{3}{2 \sqrt{7} } ori \frac{7 \sqrt{7} }{27} = +\frac{7}{18} [/tex] (mia dat raspunsul asta pt ca am simplificat
