Solve ths linear order n diferential equation correctly please

1. d y dy dy +4 +5 + 6y = 0. dx3 dx dx y dy dy 2.3-2. dx4 3. 4 4. d y dx dy dx - + - 12 dy dx dx dx3 = 0. +9y = 0, + 4y = 0, y(0) = 4, y(0) = 1, y'(0) = 9. y'(0) = -8, y" (0) = -4.