## Elementary Algebra

We use numbers that are easy to square to obtain: a) $20^2 - 2(20)(1) + 1^2 = 361$ b) $30^2 - 2(30)(1) + 1^2 = 841$ c) $50^2 - 2(50)(1) + 1^2 = 2401$ d) $80^2 - 2(80)(1) + 1^2 = 6241$ e) $40^2 - 2(40)(2) + 2^2 = 1444$ f) $60^2 - 2(60)(2) + 2^2 = 3364$