The reaction 2 NO(g) + Br₂(g) → 2 NOBr(g) is suggested to occur via
(1) Br₂ ⇌ 2 Br (fast, reversible)
(2) Br + NO ⇌ NOBr (fast, reversible)
(3) Br + NO → NOBr (slow)
Write the rate law predicted by this mechanism, expressing it only in terms of [NO] and [Br₂] (use a single proportionality constant k).