3. Решите уравнение: a) x²-32 = 0 б) 16-49у² = 0 в) (3-у)²-у(у+2,5)=9

a) $$x^2 - 32 = 0$$ $$x^2 = 32$$ $$x = \pm\sqrt{32} = \pm\sqrt{16*2} = \pm4\sqrt{2}$$ б) $$16 - 49y^2 = 0$$ $$49y^2 = 16$$ $$y^2 = \frac{16}{49}$$ $$y = \pm\sqrt{\frac{16}{49}} = \pm\frac{4}{7}$$ в) $$(3 - y)^2 - y(y + 2,5) = 9$$ $$9 - 6y + y^2 - y^2 - 2,5y = 9$$ $$9 - 8,5y = 9$$ $$-8,5y = 0$$ $$y = 0$$ Ответ: а) $$x = \pm4\sqrt{2}$$ б) $$y = \pm\frac{4}{7}$$ в) $$y = 0$$