Number 5 ABC or D? Please help

Answer:
D
Step-by-step explanation:
you want to solve it out
start with multiplying z to each. you don't multiply it to the 6 because it is in the same parenthesis set, but you multiply it to everything in the other set. After multiplying, you get: [tex]2z^3[/tex] , [tex]3z^{2}[/tex] , [tex]5z[/tex]
now do that to the 6. After multiplying you get: [tex]12z^{2}[/tex], [tex]18z[/tex], [tex]30[/tex]
now set it all next to each other [tex]2z^3[/tex] + [tex]3z^{2}[/tex] + [tex]5z[/tex] + [tex]12z^{2}[/tex] + [tex]18z[/tex] + [tex]30[/tex]
now combine like terms. start with the to the highest power. since there is only one that has a third power, you put that one first. then you combine the squared ones, and so forth.
work combining the squares: [tex]3z^{2} + 12z^{2} = 15z^{2}[/tex]
work combing the single z's: [tex]5z + 18z = 23z[/tex]
to get this: [tex]2z^3[/tex] + [tex]15z^{2}[/tex] + [tex]23z[/tex] + [tex]30[/tex]
so, the answer is D