Question

Срочно по математике даю 100 балов

Answer 1

1.

a)

$-0,2+(-\frac{1}{15})=-\frac{2}{10}-\frac{1}{15}=\frac{(-2)\cdot 3-1\cdot 2}{30}=\frac{-6-2}{30}=\frac{-8}{30}=-\frac{4}{15}$

б)

$-\frac{4}{7} +\frac{2}{9} =\frac{(-4)\cdot 9+2\cdot 7}{63}=\frac{-36+14}{63}=-\frac{22}{63}$

в)

$6,8-5\frac{1}{4}=\frac{68}{10}-\frac{21}{4}=\frac{68\cdot 2-21\cdot 5}{20}=\frac{136-105}{20}=\frac{31}{20}=1\frac{11}{20} \\ \\ 6,8 -5\frac{1}{4}=6,8-5\frac{25}{100}=6,8-5,25=1,55$

г)

$-68\cdot 0 =0$

д)

$-\frac{2}{9} \div 1,3 =-\frac{2}{9}\div\frac{13}{10} =-\frac{2}{9}\cdot\frac{10}{13} =-\frac{20}{117}$

2.

$-2-(-4)+(-5)-5,6 =-2+4-5-5,6=-3-5,6=-8,6$

3. см. приложенное фото

4.

$-\frac{2}{3}\cdot 8\cdot (-\frac{3}{9})\cdot 9=-\frac{2}{3}\cdot 8\cdot (-3)=2\cdot 8=16$