x + 1 <= -1, x # 1, x > = 1, x < 1, x # -1, x = 1, |x - 1, (x+1), x=-1, ( x + 1), x -1, ∀x ∈ (1, √(x-1)² =, X : 1, √x + 1, (x + 1, x≠1), − x =1, x+1, (x² + 1), (x² + 1)³, /x-1, X×1, x =1, x ≠ 1, x ±1, x += 1, x += 1, x:=1;, x=1, ⇔ x = 1