Respuesta :
Middle option.
(x + 1 ≤ 1) ∩ (x + 1 ≥ 1)
If you work both sides separately you get
(x ≤ 0) ∩ (x ≥ 0)
which reduces nicely to
{x | x = 0}
(x + 1 ≤ 1) ∩ (x + 1 ≥ 1)
If you work both sides separately you get
(x ≤ 0) ∩ (x ≥ 0)
which reduces nicely to
{x | x = 0}