Front Element Replace

notable

(a + b ) (a + b) = aa + 2ab + bb pairs sum of squared = square of the first-double-product of the first and the second + square of the second (a - b) (a - b) = aa - 2ab + bb subtraction binomial squared = square of the first - double the first by the second square of the second + (a + b) (a - b) = aa - bb = difference sum of squares difference