(a) Give the complete expansion of \(\left( x + \frac{2}{x} \right)^5\).

(b) In the expansion of \((a + bx^2) \left( x + \frac{2}{x} \right)^5\), the coefficient of \(x\) is zero and the coefficient of \(\frac{1}{x}\) is 80. Find the values of the constants \(a\) and \(b\).