ГДЗ по алгебре 7 класс Макарычев ФГОС Задание 906

\[\boxed{\text{906.}\text{\ }еуроки - ответы\ на\ пятёрку}\]

\[\textbf{а)}\ x² - 16 = 0\]

\[(x - 4)(x + 4) = 0\]

\[x = 4\ \ \ или\ \ \ x = - 4\]

\[Ответ:x = 4;\ \ x = - 4.\]

\[\textbf{б)}\ y² - 81 = 0\]

\[(y - 9)(y + 9) = 0\]

\[y = 9\ \ \ или\ \ \ y = - 9\]

\[Ответ:y = 9;\ \ y = - 9.\]

\[\textbf{в)}\frac{1}{9} - x^{2} = 0\]

\[\left( \frac{1}{3} - x \right)\left( \frac{1}{3} + x \right) = 0\]

\[x = \frac{1}{3}\text{\ \ }или\ \ \ \ x = - \frac{1}{3}\]

\[Ответ:\ x = \frac{1}{3};\ \ x = - \frac{1}{3}.\]

\[\textbf{г)}\ a² - 0,25 = 0\]

\[(a - 0,5)(a + 0,5) = 0\]

\[a = 0,5\ \ \ \ \ или\ \ \ \ a = - 0,5\]

\[Ответ:a = 0,5;\ \ a = - 0,5.\]

\[\textbf{д)}\ b² + 36 = 0\]

\[неверно\ при\ любом\ значении\ b.\]

\[Ответ:нет\ решения.\]

\[\textbf{е)}\ x² - 1 = 0\]

\[(x - 1)(x + 1) = 0\]

\[x = 1\ \ \ или\ \ \ x = - 1\]

\[Ответ:x = 1;\ \ x = - 1.\]

\[\textbf{ж)}\ 4x² - 9 = 0\]

\[2x = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ или\ \ \ \ \ \ 2x = - 3\]

\[x = \frac{3}{2} = 1,5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \frac{3}{2} = - 1,5\]

\[Ответ:x = 1,5;\ \ x = - 1,5.\]

\[\textbf{з)}\ 25x² - 16 = 0\]

\[(5x - 4)(5x + 4) = 0\]

\[5x = 4\ \ \ \ \ \ \ \ \ \ \ \ \ \ или\ \ \ \ \ \ \ \ 5x = - 4\]

\[x = \frac{4}{5} = 0,8\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \frac{4}{5} = - 0,8\]

\[Ответ:x = 0,8;\ \ x = - 0,8.\]

\[\textbf{и)}\ 81x² + 4 = 0\]

\[неверно\ при\ любом\ значении\ x.\]

\[Ответ:нет\ решения.\]