若m-n=4,mn=-1,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.
问题详情:
若m-n=4,mn=-1,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.
【回答】
(3)(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n+2m-m-4n-mn
=-6mn+3(m-n).
当m-n=4,mn=-1时,原式=-6×(-1)+3×4=18.
知识点:整式的加减
题型:解答题
问题详情:
若m-n=4,mn=-1,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值.
【回答】
(3)(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n+2m-m-4n-mn
=-6mn+3(m-n).
当m-n=4,mn=-1时,原式=-6×(-1)+3×4=18.
知识点:整式的加减
题型:解答题