Answer:
Step-by-step explanation:
[tex]5(x-3)=\boxed5\cdot\boxed{(x-3)}\\\\25(x-3)^3=\boxed5\cdot5\cdot\boxed{(x-3)}\cdot (x-3)\cdot(x-3)\\\\GCF\bigg(5(x-3),\ 25(x-3)^3\bigg)=\boxed5\cdot\boxed{(x-3)}=5(x-3)[/tex]