Вопрос от посетителя:
(x+3)/(x-3)-x/(x+3)=72/(x^2-9)
Илюха отвечает:
(x+3)/(x-3)-x/(x+3)=72/(x^2-9)
(x+3)/(x-3)-x/(x+3)-72/((x+3)(x-3))=0
((x+3)(x+3)-x(x-3)-72)/((x+3)(x-3)) = 0
(х²+6х+9-х²+3х-72)/(х²-9) = 0
(9х-63)/(х²-9) = 0
9х-63=0
9х=63
х = 7
Ответ. х =7.