Reduce - 2y + 5x + {x - 2[x + 3y - 4(x + y)] - 12x} porfavor ayuda?

En resumen

- 2y + 5x + {x - 2[x + 3y - 4(x + y)] - 12x} = - 2y + 5x + {x - 2[x + 3y - 4x - 4y] - 12x} = - 2y + 5x + {x - 2[ - 3x - y] - 12x} = - 2y + 5x + {x + 6x + 2y] - 12x} = - 2y + 5x + x + 6x + 2y - 12x = - 2y + 2y + 5x + x + 6x - 12x = 0 + 0 = 0.