Answer:
Step-by-step explanation:
a).
= 
= 
=
[Since, i =
]
b).
= 
= 
= 5 ± 2i [Since, i =
]
c).
= 
= 
= 
=
[Since, i =
]
No. It is not. Only what's inside counts.
Answer:
c + ab
Step-by-step explanation:
The way an expression is written is the given you have presented to us.
The commutative law of addition would turn it around as
c + ab.
It just means change the order when adding. Not all systems allow this. It matters which way you put it in some systems.