Example 110

$\;\;\;(8y^{2} + 11x^{2})(8y^{2} - 11x^{2})$

$=(A + B)( A - B) \text{ , where } A = 8y^{2} \text{ and } B = 11x^{2} $

$=A^2-B^2$

$=(8y^{2})^2 - (11x^{2})^2 $

$=64y^{4} - 121x^{4} $