Hello, Mathsnewbie!

What methods have you been taught?

And there is a typo . . .

Undetermined Coefficients

Find the G.S. given that the CF is:

Let: .[1]

. . .[2]

. . .[3]

Add [1], [2], [3]: .

And we have: .

Solve the system: .

. . Hence, the particular solution is: .

The General Solution is: .