Mình làm sai, sửa nhá!
(2x2y2-1/2)2
=(2x2y2)2 - 2. 2x2y2.1/2 + (1/2)2
=4x4y4-2x2y2+1/4
\(\left(2x^2y^2-\frac{1}{2}\right)^2=\left(2x^2y^2\right)^2-2.\left(2x^2y^2\right).\frac{1}{2}+\left(\frac{1}{2}\right)^2\)
\(=4x^4y^4-2x^2y^2+\frac{1}{4}\)
^...^ ^_^
(2x2y2-1/2)2
=(2x2y2)2- 2.2x2y2.(1/2)2+(1/2)2
=(2x2y2-1/2)2