Example 84

$\;\;\;(u + 12v)(u - 12v)$

$=(A + B)( A - B) \text{ , where } A = u \text{ and } B = 12v $

$=A^2-B^2$

$=(u)^2 - (12v)^2 $

$=u^{2} - 144v^{2} $