Example 99

$\;\;\;(2a^{10} + 5b^{11})(2a^{10} - 5b^{11})$

$=(A + B)( A - B) \text{ , where } A = 2a^{10} \text{ and } B = 5b^{11} $

$=A^2-B^2$

$=(2a^{10})^2 - (5b^{11})^2 $

$=4a^{20} - 25b^{22} $