分解因式:1.2a(x2+1)2-2ax2 2.2x2+2x+二分之一 3.a2-b2-4a+4b 4.x2+y2-1-

1.2a(x2+1)2-2ax2=2a[(x2+1)2-x2]=2a[(x2+1+x2)(x2+1-x2)]=2a(2x2+1) 2.2x2+2x+1/2=2(x2+x+1/4)=2(x+1/2)2 3.a2-b2-4a+4b=(a+b)(a-b)-4(a-b)=(a+b-4)(a-b) 4.x2+y2-1-2xy=(x2-2xy+y2)-1=(x-y)2-1=(x-y+1)(x-y-1) 5.2m(a-b)-3n(b-a)=2m(a-b)+3n(a-b)=(2m+3n)(a-b) 5.(a-b)(3a+b)2+(a+3b)2(b-a)=(a-b)[(3a+b)2-(a+3b)2]=(a-b)[(3a+b+a+3b)(3a+b-a-3b)]=(a-b)[4(a+b)(2a-2b)]=8(a+b)(a-b)2