a² + b² = ( a + b )² - 2ab. Draw a square of a size of your choice, for example 4″ on each side. a² + b²= (a+b)²- 2ab a² + b²= (a-b)²+ 2ab a² - b² = (a+b)(a-b). square identity a square minus b square is explained using geometry for better understanding. The formula for algebraic identity, a square minus b square, is explained with geometric. a plus b Squared - a plus b Square - Whole Square - Formula - Equals - (a+b)^2 = a.