Решите уравнение: a) x² - 0,64 = 0; б) 9x² - 25 = 0.

a) \(x^2 - 0.64 = 0\) \(x^2 = 0.64\) \(x = \pm \sqrt{0.64}\) \(x = \pm 0.8\) Ответ: \(x_1 = 0.8, x_2 = -0.8\) б) \(9x^2 - 25 = 0\) \(9x^2 = 25\) \(x^2 = \frac{25}{9}\) \(x = \pm \sqrt{\frac{25}{9}} \) \(x = \pm \frac{5}{3}\) Ответ: \(x_1 = \frac{5}{3}, x_2 = -\frac{5}{3}\)