Example 15

$\;\;\;(2k + l^{8})^2$

$=(A + B)^2 \text{, where } A = 2k \text{ and } B = l^{8} $

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

$=(2k)^2 + 2(2k)(l^{8}) + (l^{8})^2 $

$=4k^{2} + 4kl^{8} +l^{16} $