Example 96

$\;\;\;(5x + 7y^{11})(5x - 7y^{11})$

$=(A + B)( A - B) \text{ , where } A = 5x \text{ and } B = 7y^{11} $

$=A^2-B^2$

$=(5x)^2 - (7y^{11})^2 $

$=25x^{2} - 49y^{22} $