(1)原式=3x(1-4x2) =3x(1-2x)(1+2x);
(2)原式=2a[(x2+1)2-x2] =2x(x+12(x-1)2;
(3)原式=2(x2+x+) =2(x+)2.
(4)原式=(a2-b2)-(4a-4b) =(a+b)(a-b)-4(a-b) =(a-b)(a+b-4);
(5)原式=5bx(4a2-9y2) =5bx(2a-3y)(2a+3y);
(6)原式=(x2+y2-2xy)-1 =(x-y)2-1 =(x-y-1)(x-y+1);
(7)原式=2m(a-b)+3n(a-b) =(a-b)(2m+3n);
(8)原式=(a-b)(3a+b)2-(a+3b)2(a-b) =(a-b)[(3a+b)2-(a+3b)2] =(a-b)(3a+b-a-3b)(3a+b+a+3b) =(a-b)(2a-2b)(4a+4b) =8(a-b)2(a+b). |