6xy的平方分之X-9Y-9X平方Y分之X+3Y
问题描述：
6xy的平方分之X-9Y-9X平方Y分之X+3Y
RT
答
(x-9y)/6xy^2 -(x+3y)/9x^2y
=[3x(x-9y)-2y(x+3y)]/18x^2y^2
=(3x^2-33xy-6y^2)/18x^2y^2
=1/6y^2-11/6xy^2-1/3x^2