Thu gon về hằng đẳng thức
1) (2x+1)^2+2(2x+1)+1
2) (3x-2y)^2 +4(3x-2y)+4
3)(x+3)^2-(x-2)^2^-2(x+3)(x-2)
4)(3x-5)^2-2(3x-5)(3x+5)+(3x+5)^2
5) (x-y)^2+(x+y)^2-2(x+y)(x-y)
6) (5-x)^2+(x+5)^2-(2x+10)(x-5)
7) (x-2)^2+(x+1)^2+2(x-2)(-1-x)
8) (2x-3y)^2-(2x-3y)^2-2(4x^2-9y^2)