Example 97

$\;\;\;(k^{8} + 11l^{5})(k^{8} - 11l^{5})$

$=(A + B)( A - B) \text{ , where } A = k^{8} \text{ and } B = 11l^{5} $

$=A^2-B^2$

$=(k^{8})^2 - (11l^{5})^2 $

$=k^{16} - 121l^{10} $