Q ​Chemical reaction mechanism or a reaction is given below:

$$\begin{gathered} A_2\to 2A, k_1={10}^{5 }{s}^{-1}\left(forward\right) ,k_2={10}^{5 }{s}^{-1}\left(backward\right) \\ A+B\to AB, k_2={10}^{-1}{M}^{-1}{s}^{-1} \end{gathered}$$
Using the given chemical mechanism, write the rate law  and calculate  order of overall reaction.