已知m-n=3,mn=-1,求多项式-2mn+2m+3n-3mn-2n+2m-4n-m-mn的值

问题描述:

已知m-n=3,mn=-1,求多项式-2mn+2m+3n-3mn-2n+2m-4n-m-mn的值

-2mn+2m+3n-3mn-2n+2m-4n-m-mn
=-6mn+3m-3n
=-6mn+3(m-n)
=6+9
=15