题目内容
计算下列各题.
(1);
(2) ;
(3);
(4) .
(1)(3x+1)2(3x-1)2;
(2)(2m+3n)(2m-3n)-(3m-2n)(3m+2n);
(3)a(a+2)(a-2)-a3-1;
(4)(2x-3y-1)(2x+3y-1);
(5)1999×2001.