题目内容：

（x-4y）分之（3x)+(4y-x)分之（x+y）-（x-4y)分之（7y)

优质解答

=3x/(x-4y)-(x+y)/(x-4y)-7y/(x-4y)
=(3x-x-y-7y)/(x-4y)
=(2x-8y)/(x-4y)
=2(x-4y)/(x-4y)
=2