1、=(-2x)²-3²=4x²-92、=(3mn)²-(1/2)²-m²n²=9m²n²-1/4-m²n²=8m²n²-1/2
=[(A+2)(A-2)+4]/(A-2)]÷[A/(A-2)]=[A2/(A-2)]×[(A-2)/A]=A=(a-2)-1/(a-2)=[(a-2)^2-1]/(a-2)=(a-2+1)(a-2-1)/(a-2)=(a-1)(a-3)/(a-2)
