Respuesta :

Answer:

x = -1

Step-by-step explanation:

y + 2x = -1

Subtract 2x from both sides;

y = -2x - 1

y = 3x + 4

-2x - 1 = 3x + 4

Subtract 3x from both sides;

-5x - 1 = 4

Add 1 to both sides;

-5x = 5

Divide both sides by -5

x = -1