Решебник по математике 6 класс Виленкин ФГОС Часть 1, 2 Часть 2. П. 5. Решение уравнений Задание 65

\[\boxed{\text{5.\ 65}}\]

\[\textbf{а)}\ 7 \cdot (3x + 6) - (20x + 4) = 0\]

\[21x + 42 - 20x - 4 = 0\]

\[x + 38 = 0\]

\[x = - 38.\]

\[\textbf{б)} - 6 \cdot (4x - 3) + (7 - 6x) = 0\]

\[- 24x + 18 + 7 - 6x = 0\]

\[- 30x = - 25\]

\[x = \frac{25}{30}\]

\[x = \frac{5}{6}.\]

\[\textbf{в)} - 5 \cdot (3y + 3) + 2 \cdot (7y - 6) =\]

\[= 0\]

\[- 15y - 15 + 14y - 12 = 0\]

\[- y - 27 = 0\]

\[- y = 27\]

\[y = - 27.\]

\[\textbf{г)}\ 6 \cdot (5 - 4x) + 5 \cdot (5x + 5) = 9\]

\[30 - 24x + 25x + 25 = 9\]

\[x = 9 - 55\]

\[x = - 46.\]