Example 44

$\;\;\;(x - 11y)^2$

$=(A - B)^2 \text{, where } A = x \text{ and } B = 11y $

$=A^2 - 2AB + B^2$

$=(x)^2 - 2(x)(11y) + (11y)^2 $

$=x^{2} - 22xy +121y^{2} $