Answer:
[tex]\huge\boxed{3x}[/tex]
Step-by-step explanation:
[tex]6x+3xy+12xz\\\\6x=2\cdot \boxed{3}\cdot \boxed{x}\\\\3xy= \boxed{3}\cdot \boxed{x}\cdot y\\\\12xz=2\cdot2\cdot \boxed{3}\cdot \boxed{x}\cdot z\\\\6x+3xy+12xz= \boxed{3}\cdot \boxed{x}(2+y+2\cdot2\cdot z)=3x(2+y+4z)[/tex]
