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

$79^{2}$ can be written as $(80-1)^{2}$ We use the following formula: $(a-b)^{2}$=$a^{2}$-2ab+$b^{2}$ Plug in the values: $80^{2}$-2(80)(1)+$1^{2}$ Simplify: 6400-160+16241