［（a+b）²-（a-b）²+6a²b³］÷（-2ab）=［a²+b²+2ab-（a²+b²-2ab）+6a²b³］÷（-2ab）=（4ab+6a²b³）÷（-2ab）=-2-3ab²带入得-2-3*（-2）*1=4
