计算 3x+4y/x-y+3y/y-x-4x/x-y

问题描述:

计算 3x+4y/x-y+3y/y-x-4x/x-y

3x+4y/x-y+3y/y-x-4x/x-y
=(3x+4y)/(x-y)-3y/(x-y)-4x/(x-y)
=(3x+4y-3y-4x)/(x-y)
=(y-x)/(x-y)
=-1