Question

Задание 2(в) и если можно то и 2(б

Answer 1

Вариант 1

$0.6(4x - 12) - 0.4(5x - 7) \\ 2.4x - 7.2 - 2x + 2.8 \\ 0.4x - 4.4 = ( \frac{4}{10} \times \frac{25}{6} ) - 4.4 = \\ \frac{10}{6} - \frac{44}{10} = \frac{50 - 132}{30} = - \frac{82}{30} = \\ - \frac{41}{15} = - 2 \frac{11}{15}$

Вариант 2

$0.8(3x - 14) - 0.3(4 - 5x) = \\ 2.4x - 11.2 - 1.2 + 1.5x = \\ 3.9x - 12.4 = ( \frac{40}{13} \times \frac{39}{10} ) - 12.4 \\ = 12 - 12.4 = - 0.4$