Ordinary Differential Equations/Homogenous 3

1) $$3y''+18y'-81y=0$$

2) $$y''+6y'+13y=0$$

3) $$y''+10y'+25y=0$$

4) $$y'+24y+218y''+838y'+1369y=0$$

5) $$y'-2y-15y'+36y=0$$

6) $$y'+5y-4y'-20y=0$$

7) $$y'+4y+y'-26y=0$$