c) ∣ ∣ x ^ 2 − 4 ∣ ∣ = x ^ 2 − 4 ∀ x ∈ [ − 2 ; 2 ]

c) \(\left| {{{\rm{x}}^2} - 4} \right| = 4 - {{\rm{x}}^2}\quad \forall {\rm{x}} \in [ - 2;2]\)

=> Sai