(-m²/m-2+4/2-m)/(m+2)

问题描述:

(-m²/m-2+4/2-m)/(m+2)

(-m²/(m-2)+4/(2-m))/(m+2)
=(-m²/(m-2)-4/(m-2))/(m+2)
=-(m²-4)/[(m-2)(m+2)]
=-(m²-4)/(m²-4)
=-1