Задание №5

• $$\frac{8.1}{0.9} = 9$$, а не 0.9. Неверно
• $$\frac{9.6}{1.6} = 6$$. Верно
• $$\frac{13.2}{1.2} = 11$$, а не 1.1. Неверно
• $$\frac{9.6}{1.2} = 8$$, а не 0.8. Неверно
• $$\frac{8.2}{4.1} = 2$$. Верно

Задание №6

• $$\frac{1}{2} - \frac{9}{10} = \frac{5}{10} - \frac{9}{10} = -\frac{4}{10} = -0.4$$. Верно
• $$\frac{1}{2} - \frac{49}{20} = \frac{10}{20} - \frac{49}{20} = -\frac{39}{20} = -1.95$$, а не -1.19. Неверно
• $$\frac{1}{2} + \frac{33}{50} = \frac{25}{50} + \frac{33}{50} = \frac{58}{50} = 1.16$$. Верно
• $$\frac{1}{10} - \frac{39}{50} = \frac{5}{50} - \frac{39}{50} = -\frac{34}{50} = -0.68$$, а не 0.68. Неверно
• $$\frac{1}{10} - \frac{23}{20} = \frac{2}{20} - \frac{23}{20} = -\frac{21}{20} = -1.05$$, а не -1.5. Неверно

Задание №7

• $$-1 - 3x = 2x + 1;\ x = -0.4$$ Решение: $$-1 - 3x = 2x + 1$$ $$-3x - 2x = 1 + 1$$ $$-5x = 2$$ $$x = -\frac{2}{5}$$ $$x = -0.4$$. Верно
• $$-4x - 9 = 6x ;\ x = 0.9$$ Решение: $$-4x - 9 = 6x$$ $$-4x - 6x = 9$$ $$-10x = 9$$ $$x = -\frac{9}{10}$$ $$x = -0.9$$, а не 0.9. Неверно
• $$4 \cdot (x - 6) = 5;\ x = 7.25$$ Решение: $$4x - 24 = 5$$ $$4x = 5 + 24$$ $$4x = 29$$ $$x = \frac{29}{4}$$ $$x = 7.25$$. Верно
• $$5 \cdot (x + 4) = -9;\ x = 5.8$$ Решение: $$5x + 20 = -9$$ $$5x = -9 - 20$$ $$5x = -29$$ $$x = -\frac{29}{5}$$ $$x = -5.8$$, а не 5.8. Неверно
• $$4 \cdot (x - 2) = -1;\ x = 1.5$$ Решение: $$4x - 8 = -1$$ $$4x = -1 + 8$$ $$4x = 7$$ $$x = \frac{7}{4}$$ $$x = 1.75$$, а не 1.5. Неверно