jmc

We know that $x^2-y^2=(x+y)(x-y)$. To begin with, let $x=26^2-24^2-10$ and $y=10$. Factoring $x^2-y^2$ and substituting in gives $(26^2-24^2-10+10)(26^2-24^2-10-10)$. Now, let $x=26$ and $y=24$. Factoring $x^2-y^2$ and substituting in gives $((26+24)(26-24)-10+10)((26+24)(26-24)-10-10)$. This simplifies to $(50\cdot 2)(50\cdot 2-20)$, or $100\cdot 80$. Thus, our final answer is $\boxed{8000}$.