Respuesta :

11177420

(x, y) = (21/13 , 84/13)

Step-by-step explanation:

x + 3y = 21

- 4x + y = 0

y = 4x

_____________

x + 3y = 21

x + 3(4x) = 21

x + 12x = 21

13x = 21

x = 21/13

y = 4x

y = 4 (21/13)

y = 84/13

(x, y) = (21/13 , 84/13)