【2(X+Y)】？ -2Y(Y+2X)=4(X？ +2XY+Y？ )-2Y？ -4XY=2(2X？ +2XY+Y？ )

[3(2B)]？ - 12B(A+B)=9(A？ -4AB+B？ )- 12AB- 12B？ =3(3A？ - 16AB-B？ )

Let the side length of a square be x, which is deduced from the meaning of the question: (X+3)? =X？ +39，X=5。

(A-B)？ +B(A-B)=(A-B)(A-B+B)= A(A-B)= 2(2+ 1/2)= 5

(A+B)？ =A？ +2AB+B？ =A？ +B？ +2AB=5+4=9。

These questions are not difficult. I hope you can learn to think and do it yourself. Others are generally too lazy to answer too few questions and too many questions.