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

问题描述:

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

=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