Ответ Автор - trexshow12 2/3+(1/7+x)=5/6+1/128/12+(1/7+х)=10/12+1/128/12+(1/7+х)=11/121/7+х=11/12-8/121/7+х=3/121,7+х=1/44/28+х=7/28х=7/28-4/28х=3/28