I need help to find the convergence rate of all solution is ? I don't know how to find it

Consider the differential equation Y = -ay + b, where both a and b are positive numbers. (a) Find the general solution of the differential equation. b y (t ) = + ce-at (b) Sketch the solution for several different initial conditions. (Let a = 1 and b = 2.) 10 0.5 1.0 20 -2 0.5 1.5 2.0 -4 O-6/ o y 10 30 00 2.5 2.0 6 1.5 1.0 2 0.5 0.5 1.0 t 1.5 1.5 2.0 TO 0.5 1.0 2.0 (c) Describe how the solutions change under each of the following conditions. i. a increases As a increases, the equilibrium solution gets closer to y(t) = 0, from above . The convergence rate of all solutions is | 2 X As a increases, the solutions converge to the equilibrium solution quicker li. b increases As b increases, the equilibrium solution y(t) = _ becomes larger . The convergence rate of all solutions remains the same