Lets write this out:-
z² + z + 4z³ + 4z²
z² will become 1z² because when ever there is a varaible, and before it there is NO coefficient the coefficient automatically becomes 1. Same is with z. z will be come 1z.
Lets write it out again:-
1z² + 1z + 4z³ + 4z²
Combine like terms:-
1z² + 1z + 4z³ + 4z²
(1 + 4)z² = 5z²
1z + 5z² + 4z³
So, when combining like terms in z² + z + 4z³ + 4z² the answer is
1z + 5z² + 4z³.
Hope I helped ya!! xD
