如图,对称轴平行于y轴的抛物线与x轴交于(1,0),(3,0)两点,則它的对称轴为
(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=_________;