已知m-n=3,mn=-3,求(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)的值
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已知m-n=3,mn=-3,求(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)的值
已知m-n=3,mn=-3,求(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)的值
已知m-n=3,mn=-3,求(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)的值
(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)
=-m-4n-mn-2mn+2m+3n-3mn-2n+2m
=-m+2m+2m-4n+3n-2n-mn-2mn-3mn
=3m-3n-6mn
=3(m-n)-6mn
=3*3-6*(-3)
=9+18
=27
(1)-m-4n+3+6+2m+3n+9-2n+2m
(2)3m-3n+18
(3)9+18
(4)27
(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)
=-m-4n-mn-2mn+2m+3n-3mn-2n+2m
=3m-3n-6mn
=3(m-n)-6mn
=3x3-6x(-3)
=9+18
=27
这么简单还问!!!!去括号再化简然后代入
(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)
=-m-4n-mn-2mn+2m+3n-3mn-2n+2m(去括号)
=3m-3n-6mn(合并同项)
=3(m-n)-6mn
=3*3-6*(-3)(带入数值)
=27
(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)
=-m-4n-mn-2mn+2m+3n-3mn-2n+2m
=3m-3n-6mn
=3*3-6*(-3)
=9+18
=27
先去括号-m-4n-mn-2mn+2m+3n-3mn-2n+2m
合并同类项3m-3n-6mn
已知m-n=3,mn=-3
则原式=27