分式:m²-3m/9-m²

问题描述:

分式:m²-3m/9-m²

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