Example 105

$\;\;\;(5k^{11} + 6l^{3})(5k^{11} - 6l^{3})$

$=(A + B)( A - B) \text{ , where } A = 5k^{11} \text{ and } B = 6l^{3} $

$=A^2-B^2$

$=(5k^{11})^2 - (6l^{3})^2 $

$=25k^{22} - 36l^{6} $