5. [12 marks] Find (if possible) the general solution of each of the following 2nd-order ODEs by trying y = ell. If you can't find a solution, give a reason. (a) y" - 5y' + 6y = 0 (b) y" + xy tey = 0 (c) zy" + by' + 18y = 0 In part (c), find the solution with initial conditions y(0) = 1, y'(0) = 0