化简求值:(x^2-4x)/(x+1)除以(4-x)/x,其中x=-3

问题描述:

化简求值:(x^2-4x)/(x+1)除以(4-x)/x,其中x=-3

:(x^2-4x)/(x+1)除以(4-x)/x,
=x(x-4)/(x+1)*x/(4-x)
=-x^2/(x+1)
=-9/(-2)
=9/2