MATLAB: Am I finding the Step and Impulse Response Correctly

Question

Given the function: dy(t)/dt + 3y(t) = x(t)

step([1],[1,3],t);
impulse([1],[1,3],x,t);

Answer 1

t=0:0.1:10
step([1],[1,3],t);

%or

y=step([1],[1,3],t);
plot(y)

%and

impulse([1],[1,3],t);

%or

y=impulse([1],[1,3],t);
plot(y)

%or

N=1;
D=[1 3];
model=tf(N,D)
step(model)
figure
impulse(model)

%if x(t) is any input signal use

t=0:0.1:10;
x=exp(-t)
lsim(model,x,t)