如图,已知∠1=∠2,请你添加一个条件:__________,使△ABD≌△ACD.
(1)(6×1010)÷()=-2×105;(2)( )·(-a2x2)=-5a; (3)()÷n=a-b+2c;(4)(3x3y2+x4y2-______)÷xy=_____+____-1.
(8x2y-12x4y2)÷(-4xy)=________.
(a5b6-a3b2)÷ab=________;
3a2b2c÷(-a2b2)=________;
a2bx3÷a2x=_________;