Respuesta :

y= -3/7 (negative 3 over 7)
Well if there are no typos...

7x + y + 3 = y
7x + y - y + 3 = y - y
7x + 3 = 0
7x + 3 - 3 = -3
7x = -3
7x/7 = -3/7
x = -3/7

ANSWER: x = -3/7