945° Вправа 945Алгебра 8 клас Тарасенкова 2025 · § 23 · стор. 282

945. Скільки відсотків становить:

1) ${\displaystyle (\frac{19}{25}+0,4\cdot \frac{3}{5})\cdot 0,6=}$${\displaystyle (\frac{19}{25}+\frac{\stackrel{2}{\cancel{4}}}{\underset{5}{\cancel{10}}}\cdot \frac{3}{5})\cdot 0,6=}$${\displaystyle (\frac{19}{25}+\frac{6}{25})\cdot 0,6=}$${\displaystyle \frac{25}{25}\cdot 0,6=}$${\displaystyle 1\cdot 0,6=}$${\displaystyle 0,6}$;

${\displaystyle (-0,7+2,3):\frac{2}{3}=}$${\displaystyle 1,6:\frac{2}{3}=}$${\displaystyle \frac{\stackrel{8}{\cancel{16}}}{\underset{5}{\cancel{10}}}\cdot \frac{3}{2}=}$${\displaystyle \frac{\stackrel{4}{\cancel{8}}\cdot 3}{5\cdot \underset{1}{\cancel{2}}}=}$${\displaystyle \frac{12}{5}=}$${\displaystyle 2,4}$;

${\displaystyle \frac{0,6}{2,4}\cdot 100\mathrm{\%}=}$${\displaystyle 0,25\cdot 100\mathrm{\%}=}$${\displaystyle 25\mathrm{\%}}$;

2) ${\displaystyle (2,7-2,9)\cdot (-4,5)=}$${\displaystyle -0,2\cdot (-4,5)=}$${\displaystyle 0,9}$;

${\displaystyle 9,6\cdot \frac{5}{16}+9,06-{(-3,4)}^2=}$${\displaystyle \frac{96}{10}\cdot \frac{5}{16}+9,06-11,56=}$${\displaystyle \frac{\stackrel{6}{\cancel{96}}\cdot \stackrel{1}{\cancel{5}}}{\underset{2}{\cancel{10}}\cdot \underset{1}{\cancel{16}}}+9,06-11,56=}$${\displaystyle 3+9,06-11,56=}$${\displaystyle 12,06-11,56=}$${\displaystyle 0,5}$;

${\displaystyle \frac{0,9}{0,5}\cdot 100\mathrm{\%}=}$${\displaystyle 1,8\cdot 100\mathrm{\%}=}$${\displaystyle 180\mathrm{\%}}$.