## Algebra: A Combined Approach (4th Edition)

$x^{4}-25$
$(x^{2}+5)(x^{2}-5)$ Perform this product applying the following formula: $(a+b)(a-b)=a^{2}-b^{2}$ Here, $a=x^{2}$ and $b=5$ $(x^{2}+5)(x^{2}-5)=(x^{2})^{2}-(5)^{2}=x^{4}-25$