1.
[tex]2\frac{1}{2}:1\frac{1}{3}+4\frac{3}{4}\cdot(-3\frac{2}{5}) = \frac{5}{2}:\frac{4}{3}+\frac{19}{4}\cdot(-\frac{17}{5}) =\frac{5}{2}\cdot\frac{3}{4}-\frac{323}{20} = \frac{15}{8}-\frac{323}{20} = \frac{75}{40}-\frac{646}{40} =\\\\=-\frac{571}{40} = -14\frac{11}{40}[/tex]
2.
[tex]-6\frac{2}{5}:\frac{-3\frac{4}{5}-(-1\frac{1}{3})}{4} = -\frac{32}{5}:\frac{\frac{-19}{5}+\frac{4}{3}}{4} = -\frac{32}{5}:\frac{-\frac{57}{15}+\frac{20}{15}}{4}=-\frac{32}{5}:\frac{-\frac{37}{15}}{4}=\\\\=-\frac{32}{5}:(-\frac{37}{60})=-\frac{32}{5}\cdot(-\frac{60}{37}) = -32\cdot(-\frac{12}{37}) = \frac{384}{37} = 10\frac{14}{37}[/tex]
3.
[tex][(-\frac{2}{5})^{2}-\frac{3}{5}\cdot(\frac{2}{3})^{3}]:1\frac{14}{15} = (\frac{4}{25}-\frac{3}{5}\cdot\frac{8}{27}):\frac{29}{15} =(\frac{4}{25}-\frac{8}{15})\cdot\frac{15}{29} =(\frac{12}{75}-\frac{40}{75})\cdot\frac{15}{29}=\\\\=-\frac{28}{75}\cdot\frac{15}{29} = -\frac{28}{5\cdot29} = -\frac{28}{145}[/tex]
