[﹙m²﹣5m＋6﹚／﹙m²－3m﹚]·[m²＋﹙m/m－2﹚]
=[(m-2)(m-3)/m(m-3)](m²+1-2)
=[(m-2)/m](m²-1)
=(m³-m-2m²+2)/m
=m²-2m-1+2/m这一步[m²＋﹙m/m－2﹚]是怎么变成(m²+1-2)这样的?难道原题没表达清楚 应该是m/(m－2) ?是的晕..那得重来 [﹙m²﹣5m＋6﹚／﹙m²－3m﹚]·[m²＋﹙m/m－2﹚]=[(m-2)(m-3)/m(m-3)][(m³-2m²)/(m-2)+m/(m-2)] （把m²化成分母是m-2的分数）=[(m-2)/m](m³-2m²+m)/(m-2)=(m-2)/m ×m(m²-2m+1)/(m-2)=m²-2m+1