Answer:
=

Explanation:
Step(i):-
Given

Factors of s² + 3s - 4
= s² + 4s - s -4
= s( s +4 ) -1 (s +4)
= (s-1)(s+4)
=

By using partial fractions
..(i)
s = A ( s-1) + B( s+4) ....(ii)
Put s= 1 in equation (ii) , we get
1 = B(5)

s = -4 in equation (ii) , we get
-4 = -5A

Step(ii):-
now the equation (i) , we get

By using inverse Laplace transform formula



=
