Найдите все нецелые числа x,y,z, такие, что x+y=5xy,x+z=6xz,y+z=7yz
Ответ:
(1/5; 1/7; 1/6) && (1/6; 1/5; 1/7)
Пошаговое объяснение:
x + y = 5xy
x + z = 6xz
y + z = 7yz
_________
(5x - 1)(5y - 1) = 0
(6x - 1)(6z - 1) = 0
(7y - 1)(7z - 1) = 0
_____
1) 5x - 1 = 0
x = 1/5
=> 6z - 1 = 0 => z = 1/6
=> 7y - 1 = 0 => y = 1/7
2) 5y - 1 = 0
y = 1/5
=> 7z - 1 = 0 => z = 1/7
=> 6x - 1 = 0 => x = 1/6