Answer:
3z^2
Step-by-step explanation:
Factors of the different terms are ...
12z^3 = 2·2·3·z·z·z
45z^2 = 3·3·5·z·z
18z^5 = 2·3·3·z·z·z·z·z
The common factors are 3 and z·z.
The greatest common factor is 3z^2.
