(1)-4a3b2+10a2b-2ab=-2ab(2a2b-5a+1);
(2)6(x+y)2-2(x+y),
=2(x+y)[3(x+y)-1],
=2(x+y)(3x+3y-1);
(3)-7ax2+14axy-7ay2,
=-7a(x2-2xy+y2),
=-7a(x-y)2;
(4)25(a-b)2-16(a+b)2,
=[5(a-b)-4(a+b)][5(a-b)+4(a-b)],
=(9a-b)(a-9b);
(5)(x2+y2)2-4x2y2,
=[(x2+y2)-2xy][(x2+y2)+2xy],
=(x+y)2(x-y)2;
(6)a2+2ab+b2-1,
=(a+b)2-1,
=(a+b+1)(a+b-1).