已知m-n=4,mn=2,求多项式(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.

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已知m-n=4,mn=2,求多项式(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.

已知m-n=4,mn=2,求多项式(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.
已知m-n=4,mn=2,求多项式(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.

已知m-n=4,mn=2,求多项式(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.
解(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n+2m-m-4n-mn
=-2mn-3mn-mn+2m+2m-m+3n-2n-4n
=-6mn+3m-3n
=-6*2+3(m-n)
=-12+3*4
=0

0

原式化简为=-6mn+3m-3n=-6*2+3*4=0

原式=-2mn+2m+3n-3mn-2n+2m-m-4n-mn
=-6mn+3m-3n
=-(6乘以mn)+3乘以(m-n)
=-(6乘以2)+3乘以4
=-12+12
=0
我写的减号有点小,要仔细看哟