【m-(2n-3)][m+(2n-3)]=m^2-(2n-3)^2=m^2-4n^2+12n-9如有疑问,请追问;如已解决,请采纳
(m-2n+3)(m+2n-3)=[m-(2n-3)](m+2n-3)=m的平方-(2n-3)的平方=-4n的平方+m的平方+12n-9
[m-(2n-3)][m+(2n-3)]=m^2-(2n-3)^2做到这一步就差不多了
[m-(2n-3)][m+(2n-3)]
-9(m-2n)(m+2n)=-9m方+36n方