计算下列各题:(15分)
(1)(5m3n2)2·(-2m2)3·(-n3)4; (2)(-3)0+(-0.125)2009×82009;
(3)(2am-3bn)(3an+5bm); (4)(x+y)(x-y)-(x-y)2;
(5)(66x6y3-24x4y2+9x2y)÷(-3x2y).
的结果为 .
.若,,则 .
.[(a-b+c)(a-b-c)+c2]÷(a-b)=_____.
若(x+6)(x+2)=x(x-3)-21,则x=_______.
已知am=2,an=3,则a2m-3n=______.