Continuous-Time System:
a1 = 21, a0 = 12, b1 = -2, b0 = -8, 

Your excitation signal x(t) consists of straight lines connecting these points.
It has been zero up until the first time and is zero after the last time.

t = 1.20992, x(t) = 0
t = 1.20992, x(t) = 3
t = 4.55151, x(t) = 3
t = 4.55151, x(t) = 11
t = 7.31146, x(t) = 11
t = 7.31146, x(t) = 10
t = 9.64549, x(t) = 10
t = 9.64549, x(t) = -16
t = 9.64952, x(t) = -16
t = 9.64952, x(t) = 0
t = 14.6364, x(t) = 0

Discrete-Time System:
a0 = -10, a1 = -7, b0 = -11, b1 = -27, 
0 <= n < 4,  x[n] = 0
4 <= n < 8,  x[n] = 6
8 <= n < 10,  x[n] = -8
10 <= n < 12,  x[n] = -6
12 <= n < 26,  x[n] = 0

x[n] has been zero up until the first time and is zero after the last time.