Use the method of undetermined coefficients to find #6 & #7 please

For each of the following problems, find the general solution of the given differential equation, and solve the initial value problem when initial values are given. 1. y" + 5y' -6y = 22 -18t2 2. y" - 4y' + 5y =1+5t 3. y' + 4y' = 12 + 1 4. y" + 6y' + 10y = 20t, y(0) = 0, y'(0) = 4 5. y" - 3y' = 4t - 3. 6. y" - y' = 3t, y(0) = 2, y'(0) = -2. 7. y" - 6y' + 9y =t-1, y(0) =0, y'(0) = 3