Решите уравнение: a) (2x – 5)² – (2x – 3)(2x + 3) = 0; б) 9y² – 25 = 0.

a) $$(2x - 5)^2 - (2x - 3)(2x + 3) = 0$$ $$(4x^2 - 20x + 25) - (4x^2 - 9) = 0$$ $$4x^2 - 20x + 25 - 4x^2 + 9 = 0$$ $$-20x + 34 = 0$$ $$-20x = -34$$ $$x = \frac{-34}{-20} = \frac{17}{10} = 1.7$$ б) $$9y^2 - 25 = 0$$ $$9y^2 = 25$$ $$y^2 = \frac{25}{9}$$ $$y = \pm \sqrt{\frac{25}{9}} = \pm \frac{5}{3}$$ Ответы: a) $$x = 1.7$$ б) $$y = \pm \frac{5}{3}$$