## Precalculus (6th Edition) Blitzer

$(4x-5)^{2}$
The first and last terms are perfect squares, $16x^{2}=(4x)^{2}$ $25=5^{2}$ The middle term is $-2(4x)(5)$, so we apply the formula: $(A-B)^{2}=A^{2}-2AB+B^{2}$ $=(4x-5)^{2}$