Answer:
5(x + 7)²
Step-by-step explanation:
[tex]5(x+7)^4=\boxed5\cdot\boxed{(x+7)}\cdot\boxed{(x+7)}\cdot(x+7)\cdot(x+7)\\\\35(x+7)^2=\boxed5\cdot7\cdot\boxed{(x+7)}\cdot\boxed{(x+7)}\\\\15(x+7)^3=\boxed5\cdot3\cdot\boxed{(x+7)}\cdot\boxed{(x+7)}\cdot(x+7)\\\\GCF\bigg(5(x+7)^4,\ 35(x+t)^2,\ 15(x+7)^3\bigg)=\boxed5\cdot\boxed{(x+7)}\cdot\boxed{(x+7)}\\\\=5(x+7)^2[/tex]
