1-7 пожалуйста Дам 60 балов

1) -21 + 84:7 = -21 + 12 = -9;

2) 37 - 29 + 159 - 86 = 37 + 130 - 86 = 167 - 86 = 81;

3) -26 + 13 · 6 = -26 + 13 · 2 · 3 = -26 + 26 · 3 = 26 · 2 = 52;

4) $\frac{11}{15}-\frac{7}{6}\cdot\frac{8}{35}=\frac{11}{15}-\frac{7\cdot8}{6\cdot35} = \frac{11}{15}-\frac{4}{15}=\frac{7}{15}$

5) $(\frac{12}{7}-\frac{20}{21})\cdot\frac{56}{16}=(\frac{36}{21}-\frac{20}{21})\cdot\frac{56}{16} = \frac{16}{21}\cdot\frac{56}{16}=\frac{16\cdot56}{21\cdot16}=\frac{8}{3}=2\frac{2}{3}$

6) $\frac{107}{89}\cdot \frac{64}{70}+\frac{107}{89}\cdot \frac{25}{70}=\frac{107}{89}(\frac{64}{70}+\frac{25}{70}) = \frac{107}{89}\cdot\frac{64+25}{70}=\frac{107\cdot89}{89\cdot70}=\frac{107}{70}=1\frac{37}{70}$

7) х - искомое число

x + 77 = $\frac{10}{3}x$

x - $\frac{10}{3}x$ = -77;

$-\frac{7}{3}x$ = -77;

x = -77 : ( $-\frac{7}{3}$ )

x = $\frac{3}{11}$

Ответ: $\frac{3}{11}$