A=3m的平方+2n的平方,B=m的平方-2mn+n的平方,
当lml=2n,n=1,且mn<0时
lml=2
mn<0
m=-2
2A-3B
=2(3m^2+2n^2)-3(m^2-2mn+n^2)
=6m^2+4n^2-3m^2+6mn-3n^2
=3m^2+n^2+6mn
=3*(-2)^2+1^2+6*(-2)*1
=12+1-12
=1
A=3m的平方+2n的平方,B=m的平方-2mn+n的平方,
当lml=2n,n=1,且mn<0时
lml=2
mn<0
m=-2
2A-3B
=2(3m^2+2n^2)-3(m^2-2mn+n^2)
=6m^2+4n^2-3m^2+6mn-3n^2
=3m^2+n^2+6mn
=3*(-2)^2+1^2+6*(-2)*1
=12+1-12
=1