Answer:
rate = k*[A]^3
Explanation:
The following information is missing in the question:
Consider the following elementary steps that make up the mechanism of a certain reaction
1. 3A -> B+C
2. B+2D -> C+F
In elementary reactions, the order of each reactant in the rate law is equal to the coefficient in the balanced equation. Therefore, for the first step:
rate = k*[A]^3