Question

Sa se determine numarul elementelor multimii A={x €Z/|x+1|<2}

Answer 1

A = { x ∈ Z │ |x+1| ≤ 2 }

|x+1| ≤ 2 

-2 ≤ x+1 ≤ 2    ⇒  x + 1 ∈ {-2, -1, 0, 1, 2 } | - 1
 
                            x ∈ {-3, -2, -1, 0, 1}

    card A = 5 elemente
 

Answer 2

-2 ≤ | x+1| ≤ 2

-2 ≤ x+1 ≤ 2 |-1

-3 ≤ x ≤ 1 =>A={ -3,-2,-1,0,1}