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

$4y^{4}-1$
$(2y^{2}-1)(2y^{2}+1)$ To evaluate this product, use the following formula: $(a-b)(a+b)=a^{2}-b^{2}$ Here, $a=2y^{2}$ and $b=1$ $(2y^{2}-1)(2y^{2}+1)=(2y^{2})^{2}-(1)^{2}=4y^{4}-1$