_x_ + _y_                    _a_ - _b_                   Плииз...

_x_ + _y_                    _a_ - _b_                   Плииз помогите=)))    

x-y     y-x                    12m  18n                        

Ответ:

a)

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

б)

a/12m -b/18n = (3an-2bm)/36mn

Источник: https://znanija.com/task/263457