4mn+1/9-4m²-n²怎么因式分解

4mn+1/9-4m²-n²怎么因式分解
4mn+1/9-4m²-n²怎么因式分解

4mn+1/9-4m²-n²怎么因式分解
4mn+1/9-4m²-n²=-(2m-n)²+(1/3)²=(1/3+2m-n)(1/3-2m+n)

=1/9-(4m2-4mn+n2)=(1/3)2-(2m-n)2=(1/3+2m-n)(1/3-2m+n)

原式=1/9-(2m-n)^2=(1/3)^2-(2m-n)^2=(1/3+2m-n)(1/3-2m+n)