tgx - 6ctgx + 5 = 0 tgx -6/tgx +6 = 0 tg2x + 5tgx - 6 = 0 Замена tgx = t t2 + 5t - 6 = 0 D = 25+24 = 49 t1 = (-5+7) / 2= 1 t2 = (-5-7) / 2 = -6 tgx = 1 x = п/4 + пn, n tgx = -6 x = -arctg 6+ пn