Final answer:
To solve the given initial value problem, we can use the method of undetermined coefficients. The complementary solution of the homogeneous equation y'' + y' - 12y = 0 is y_c = c1e^(-4t) + c2e^(3t), where c1 and c2 are constants. By finding the particular solution and adding it to the complementary solution, we can obtain the complete solution.
Step-by-step explanation:
To solve the given initial value problem, we can use the method of undetermined coefficients. The complementary solution of the homogeneous equation y'' + y' - 12y = 0 is y_c = c1e^(-4t) + c2e^(3t), where c1 and c2 are constants. To find the particular solution, we assume y_p = Ae^t + Be^(2t) + C, where A, B, and C are constants. By substituting this into the differential equation and solving for A, B, and C, we can find the particular solution y_p.
We can then add the complementary and particular solutions to get the general solution, which is y = y_c + y_p. Finally, we can use the initial conditions y(0) = 1 and y'(0) = 3 to determine the values of the constants and obtain the complete solution.