Respuesta :

Answer:

z= 4-x-y

z= -1+4x-y

z= 2-x

Jsf09

Step-by-step explanation:

z = 2-x

y = -1-z +4x

substitute

x -1 -2+x +4x + 2 -x = 4

-1 + 5x = 4

5x = 5

x = 1

z = 1

1+y+1 = 4

y = 2