Solve the initial value problems in Problems 18 through 22. First make a substitution of the form t = x - a, then find a solution Σcntⁿ of the transformed differential equation. State the interval of values of x for which Theorem 1 of this section guarantees convergence.

(4x² + 16x + 17) y" = 8y; y(-2) = 1, y'(-2) = 0

THEOREM 1 Solutions Near an Ordinary Point Suppose that a is an ordinary point of the equation A(x)y" + B(x)y' + C(x) y = 0; (1) that is, the functions P = B/A and Q = C/A are analytic at x = a. Then Eq. (1) has two linearly independent solutions, each of the form y(x) = [cn (x-a)". n=0 (5) The radius of convergence of any such series solution is at least as large as the distance from a to the nearest (real or complex) singular point of Eq. (1). The coefficients in the series in (5) can be determined by its substitution in Eq. (1).