完全平方公式题(2)注:括号后的数为次方 (2X+Y-3)2(A+3B-2)(A-3B+2)(X+Y+1)(1-X-Y)

(2X+Y-3)^2 =(zx+y)^2-6(2x+y)+9=z^2 x^2+2xyz+y^2-12x-6y+9
(A+3B-2)(A-3B+2) =[a+(3b-2)][a-(3b-2)]=a^2-(3b-2)^2=a^2-9b^2+12b-4
(X+Y+1)(1-X-Y)=-(x+y-1)(x+y+1)=-(x+y)^2+1=-x^2-2xy-y^2+1
[X+(Y+1)][X-(Y+1)]=x^2-(y+1)^2=x^2-y^2-2y-1
(3X+Y-4)(3X+Y+4)-(3X+Y+4)(3X-Y-4)
=(3x+y)^2-16-(3x)^2+(y+4)^2
=9x^2+6xy+y^2-16-9x^2+y^2+8y+16
=6xy+2y^2+8y