3. Решите уравнение: a) 4²-x²= 0 б) 16-9у² = 0 в) (2-у)²-у(у+2,5)=4

a) \(4^2 - x^2 = 0\) => \(16 - x^2 = 0\) => \((4 - x)(4 + x) = 0\) => \(x = 4\) или \(x = -4\) б) \(16 - 9y^2 = 0\) => \(9y^2 = 16\) => \(y^2 = \frac{16}{9}\) => \(y = \frac{4}{3}\) или \(y = -\frac{4}{3}\) в) \((2 - y)^2 - y(y + 2.5) = 4\) => \(4 - 4y + y^2 - y^2 - 2.5y = 4\) => \(-6.5y = 0\) => \(y = 0\)