Answer: 10z + 6
Explanation:
this is a short problem.. sometimes you would need to distribute, but since there is no number in front of parenthesis you can just get rid of them
that gives you: 3z + 1 +5 + 7z
now from here we combined liked terms
7z + 3z = 10z
1 + 5 = 6
so that gives you: 10z + 6