(1)7x2-63=______;
(2)9-12t+4t2=______;
(3)-2x3+4x2-2x=______;
(4)(a2+4)2-16a2=______.
网友回答
解:(1)7x2-63=7(x2-9)=7(x+3)(x-3);
(2)9-12t+4t2=32-3?(2t)?2+(2t)2=(3-2t)2;
(3)-2x3+4x2-2x=-2x(x2-2x+1)=2x(x-1)2;
(4)(a2+4)2-16a2=(a2+4-4a)(a2+4+4a)=(a-2)2(a+2)2.
故