Example 30

$\;\;\;(7x^{7}y^{2} + 5)^2$

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

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

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

$=49x^{14}y^{4} + 70x^{7}y^{2} +25 $