[tex]\frac{(\frac{2}{7})^{-2}-7\cdot(1\frac{1}{3})^{-1}}{(\frac{3}{7})^{-1}+2\frac{1}{3}}=\frac{(\frac{7}{2})^{2}-7\cdot(\frac{4}{3})^{-1}}{(\frac{7}{3})^{1}+2\frac{1}{3}}=\frac{\frac{49}{4}-7\cdot(\frac{3}{4})^1}{\frac{7}{3}+\frac{7}{3}}=\frac{\frac{49}{4}-7\cdot\frac{3}{4}}{\frac{14}{3}}=\frac{\frac{49}{4}-\frac{21}{4}}{\frac{14}{3}}=\\\\\frac{\frac{28}{4}}{\frac{14}{3}}=\frac{7}{\frac{14}{3}}=7:\frac{14}{3}=7\cdot\frac{3}{14}=\frac{3}{2}=1\frac{1}{2}[/tex]
