## Algebra 1: Common Core (15th Edition)

$16x^{2}+160x+400$.
The side length of the expanded deck is $4(x+5)=4x+20$ The area of the expanded deck is $(4x+20)^{2}$ ...square the binomial. $=(4x)^{2}+2(4x)(20)+20^{2}$ ...simplify. $=16x^{2}+160x+400$ The area of the expanded deck is $16x^{2}+160x+400$.