已知m-n=4,mn=1,则(2m+3n-2mn)-(m+4n)-(3mn+2n-2m)=_____

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已知m-n=4,mn=1,则(2m+3n-2mn)-(m+4n)-(3mn+2n-2m)=_____
已知m-n=4,mn=1,则(2m+3n-2mn)-(m+4n)-(3mn+2n-2m)=_____

已知m-n=4,mn=1,则(2m+3n-2mn)-(m+4n)-(3mn+2n-2m)=_____

(2m+3n-2mn)-(m+4n)-(3mn+2n-2m)
=2m+3n-2mn-m-4n-3mn-2n+2m
=(2-1+2)m+(3-4-2)n+(-2-3)mn
=3m-3n-5mn
=3(m-n)-5mn
=3×4-5×1
=7

原式=2m+3n-2mn-m-4n-3mn-2n+2m=3m-3n-5mn=3(m-n)-5mn=12-5=7

(2m+3n-2mn)-(m+4n)一(3mn+2n-2m)
=2m+3n-2mn-m-4n-3mn-2n+2m
=3m-3n-5mn
=3(m-n)-5mn
=3×4-5×1
=7

7