If x = 2 + 5i where i = \(\sqrt{-1}\) and 2\(\left(\frac{1}{1!9!}+\frac{1}{3!7!}\right)\) + \(\frac{1}{5!5!}\) = \(\frac{2^a}{b!}\), then value of (x³ – 5x² + 33x – 19) is equal to