9. (20 points) Let f(x) = En=] an (x - 2)" be a function represented as a power series centered at I = 2, where {an } is a sequence of coefficients. Given that f is continuous, differentiable, and satisfies the equation 2f(x) - f'(x) = x for all x in its interval of convergence, find the first four non-zero terms of the sequence {an}