Answer:
[tex]3b\left(7c+3a\right)[/tex]
Step-by-step explanation:
[tex]18bc+9ab+3cb[/tex]
[tex]=6\cdot \:3bc+3\cdot \:3ba+3bc[/tex]
[tex]=3b\left(6c+3a+c\right)[/tex]
[tex]=3b\left(7c+3a\right)[/tex]
