计算:
(1)a2•a5+a•a3•a3
(2)-(-x2)3•(-x2)2-x•(-x3)3
(3)(2x-1)(2x+1)(x2+x+1)
(4)(3x-2y+1)(3x+2y-1)
(1)a2•a5+a•a3•a3,
=a7+a7,
=2a7;
(2)-(-x2)3•(-x2)2-x•(-x3)3,
=x10+x10,
=2x10;
(3)(2x-1)(2x+1)(x2+x+1),
=(4x2-1)(x2+x+1),
=4x4+4x3+3x2-x-1;
(4)(3x-2y+1)(3x+2y-1),
=[3x-(2y-1)][3x+(2y-1)],
=9x2-4y2+4y-1.