分式:m²-3m/9-m²
问题描述：
分式:m²-3m/9-m²
答
m²-3m/9-m² ＝m(m-3)/-(m+3)(m-3)=-m/(m+3)
答
-m(3-m)/(3-m)(3+m),化简得：-m/(3+m)
答
m²-3m/9-m²
=m(m-3)/(3-m)(3+m)
=-m(3-m)/(3-m)(3+m)
=-m/3+m 同项相消
答：原式为-m/m+3