-(3m^2-mn+n^2)-(4m^2-2mn-n^2)
=-3m^2+mn-n^2-4m^2+2mn+n^2
=-7m^2+3mn
m=-1/2,n=-1/3
所以
原式=-7*1/4+3*(-1/2)*(-1/3)
=-7/4+3/2
=-1/4
-(3m^2-mn+n^2)-(4m^2-2mn-n^2) m=-1/2,n=-1/3
-(3m^2-mn+n^2)-(4m^2-2mn-n^2) m=-1/2,n=-1/3
数学人气:555 ℃时间:2020-04-12 14:50:20
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