解:原式= ①
= ②
=3﹣4﹣ ③
=3﹣4﹣ ﹣1+2④
=﹣ .
①4a3b÷2a2=2a,②﹣12x4y3÷2x2y=6x2y2 , ③﹣16a2bc÷ a2b=﹣4c,④(﹣ ab2)3÷(﹣ ab2)= a2b4 .