Решим уравнение
5у² + 9у - 2 = 0
D = b² - 4ac
D = 9² - 4 * 5 * (-2) = 81 + 40 = 121
√D = √121 = 11
y₁ = (- 9 + 11)/(2 * 5) = 2/10 = 1/5
y₂ = (- 9 - 11)/(2 * 5) = - 20/10 = - 2
y₁ = 1/5
y₂ = - 2
5y² + 9y - 2 = 5 * (y - y₁) * (y - y₂)- 2 = 5 * (y - 1/5) * (y - (-2)) = (5y -1) * (y + 2)
Ответ: 5y² + 9y - 2 = (5y -1) * (y + 2)