The radioactive isotope of iodine, 1- 1 35, decays into the radioactive isotope Xe- 1 35 of xenon; this in tum decays into another (stable) product. The half-lives of iodine and xenon are 6.7 hours and 9.2 hours, respectively.
(a) Write a system of differential equations descnbing the amounts of 1- 135 and Xe- 135 present at any time.
(b) Obtain the general solution of the system found in part (a).