Example 33

$\;\;\;(7a^{6}b^{7} + 4)^2$

$=(A + B)^2 \text{, where } A = 7a^{6}b^{7} \text{ and } B = 4 $

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

$=(7a^{6}b^{7})^2 + 2(7a^{6}b^{7})(4) + (4)^2 $

$=49a^{12}b^{14} + 56a^{6}b^{7} +16 $