Example 57

$\;\;\;(8x^{9} - 7y^{5})^2$

$=(A - B)^2 \text{, where } A = 8x^{9} \text{ and } B = 7y^{5} $

$=A^2 - 2AB + B^2$

$=(8x^{9})^2 - 2(8x^{9})(7y^{5}) + (7y^{5})^2 $

$=64x^{18} - 112x^{9}y^{5} +49y^{10} $