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

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