[tex]a) \ (\frac{6}{7}-\frac{9}{14})\cdot2\frac{1}{3}+(7-6\frac{7}{20}):6\frac{1}{2} =(\frac{12}{14}-\frac{9}{14})\cdot\frac{7}{3}+(\frac{140}{20}-\frac{127}{20}):\frac{13}{2} =\\\\=\frac{3}{14}\cdot\frac{7}{3}+\frac{13}{20}\cdot\frac{2}{13} = \frac{1}{2}+\frac{1}{10} = \frac{5}{10}+\frac{1}{10} = \frac{6}{10} = \frac{3}{5}[/tex]
[tex]b) \ (1,25:2,5+0,5\cdot0,35):0,05 =(\frac{125}{100}:\frac{25}{10}+\frac{5}{10}\cdot\frac{35}{100}):\frac{5}{100}=\\\\=(\frac{5}{4}:\frac{5}{2}+\frac{1}{2}\cdot\frac{7}{20}):\frac{1}{20}=(\frac{5}{4}\cdot\frac{2}{5}+\frac{7}{40})\cdot20 = (\frac{10}{20}+\frac{7}{40})\cdot20 =(\frac{20}{40}+\frac{7}{40})\cdot20 = \frac{27}{40}\cdot20=\\\\=\frac{27}{2} = 13\frac{1}{2} = 13,5[/tex]
[tex]c) \ (27\cdot\frac{1}{9}+6,4\cdot\frac{1}{4})-(3,6:1\frac{1}{2}-2\frac{1}{4}:1,5) =\\\\= (0,3+1,6) - (3,6:1,5-2,25:1,5)=1,9 -(3,6-2,25):1,5 =\\\\= 1,9 -1,35:1,5 =1,9 - 0,9 = 1[/tex]
[tex]d) \ (-3)\cdot5 - 2\cdot(-8) = -15+16 = 1[/tex]
[tex]e) \ (-15):(-3)\cdot(-2):5 = 5\cdot(-\frac{2}{5}) = -2[/tex]
