(5a-4) - (2a-1)(3a+7) = 5a - 4 - (6a^2 + 14a - 3a - 7) = 5a - 4 - (6a^2 + 11a - 7) =5a - 4 - 6a^2 - 11a + 7 = -6a^2 - 6a + 3 или -(6a^2 + 6a - 3)
(5a-4) - (2a-1)(3a+7) = 5a - 4 - (6a^2 + 14a - 3a - 7) = 5a - 4 - (6a^2 + 11a - 7) =5a - 4 - 6a^2 - 11a + 7 = -6a^2 - 6a + 3 или -(6a^2 + 6a - 3)