Use the Laplace transform to solve the following initial value problem:
y'' + 4y' - 21y = 0
y(0) = 2, y'(0) = -3
First, using Y for the Laplace transform of y(t), i.e., Y = L{y(t)}, find the equation you get by taking the Laplace transform of the differential equation.
Now solve for Y(s) and write the above answer in its partial fraction decomposition, Y(s) = A/(s+a) + B/(s+b) where a < b
Now by inverting the transform, find y(t).