A B + PBZ: s+ ·37)·(s+ 1 + s + s+ 37 τ B S¹: so: A 1 = As + + + B + 3/4 A = -B 1 = 3 A A-T 33 τ τ I Bs A 2A 3τ 3τ 3τ 3τ A-37 = 2

The fraction PBZ is in Laplace domain and coefficients A and B need to be determined. Solution is given, however steps s⁰ and s¹ are not clear enough. Please explain steps s⁰ and s¹