How do you do it.
If a voltage is 4V I know that the s-domain is 4/s.
What is 6A in s-domain?

I am referring to the question in the jpeg.
I cannot use source transformation since the 6A is not parallel to a resistor.
I only managed to work out the inductor current as 4A.

 

Any constant source of value K - current or voltage - is just K/s