ГДЗ по алгебре 9 класс Макарычев Задание 29

\[\boxed{\text{29\ (29).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)} - 0,5x(3x - 4) + 15x =\]

\[= 4 \cdot (1,5x + 1) + 3\]

\[- 1,5x + 2 + 15x = 6x + 4 + 3\]

\[- 1,5x + 15x - 6x = 7 - 2\]

\[7,5x = 5\]

\[x = \frac{5}{7,5} = \frac{50}{75}\]

\[x = \frac{2}{3}\]

\[Ответ:x = \frac{2}{3}.\]

\[\textbf{б)}\ (2x - 3)(2x + 3) - x^{2} =\]

\[= 12x - 69 + 3x^{2}\]

\[4x^{2} - 9 - x^{2} = 12x - 69 + 3x^{2}\]

\[4x^{2} - x^{2} - 3x^{2} = 12x - 69 + 9\]

\[12x - 60 = 0\]

\[12x = 60\]

\[x = 5\]

\[Ответ:x = 5.\]