Answer:
[tex]\large\boxed{5p^2-10pq+5p^2-80=5(p-q-4)(p-q+4)}[/tex]
Step-by-step explanation:
[tex]5p^2-10pq+5q^2-80\\\\=5(\underbrace{p^2-2pq+q^2}_{(*)}-16)\qquad\text{use}\ (a-b)^2=a^2-2ab+b^2\qquad(*)\\\\=5\bigg((p-q)^2-16\bigg)\\\\=5\bigg((p-q)^2-4^2\bigg)\qquad\text{use}\ a^2-b^2=(a-b)(a+b)\\\\=5(p-q-4)(p-q+4)[/tex]
