We give a closed form for the unique solution to the n X n regressive time varying linear dynamic system of the form x'^it) = A(t)x(t),x{to) = xg, via use of a newly developed generalized form of the PeanoBaker series. We develop a power series representation for the generalized time scale matrix exponential when the matrix A{t) = A is a constant matrix. We also introduce a finite series representation of the matrix exponential using the Laplace transform for time scales, as well as a theorem which allows us to write the matrix exponential as a series of (n -1) terms of scalar C^(T, R) functions multiplied by powers of the system matrix A.