m²+(n-mn)²+2mn-2m²n
=m²+n²-2mn²+m²n²+2mn-2m²n
=m²+2mn+n²-2mn²+m²n²-2m²n
=(m+n)²-mn(2n-mn+2m)
=(m+n)²-mn(2(m+n)-mn)
=3²-3/2(2*3-3/2)(接下你自己算把)
m²+(n-mn)²+2mn-2m²n
=m²+n²-2mn²+m²n²+2mn-2m²n
=m²+2mn+n²-2mn²+m²n²-2m²n
=(m+n)²-mn(2n-mn+2m)
=(m+n)²-mn(2(m+n)-mn)
=3²-3/2(2*3-3/2)(接下你自己算把)