Reaction Mechanism Rate Law

The following initial rate data was collected for the reaction, A + 2B $\longrightarrow$ products

B. Find the rate constant

The following initial rate data was collected for the reaction, 2 NO + O$_2$ $\longrightarrow$ 2NO$_2$

[NO$_2$]$^X$[O$_2$]$^Y$

Below is a proposed mechanism for a reaction, with k1 > k2. What is the rate law?

$NO_2 + CO~ \xrightarrow{k_1}~ NO + NO_3$

$NO_3 + CO~ \xrightarrow{k_2}~ NO_2 + CO_2$

Below is a proposed mechanism for a reaction, with k1 > k2. What is the rate law?

$NO+ Br_2~ \mathop{\leftrightharpoons}^{k_1}_{k_{-1}}~ NOBr_2$

$NOBr_2 + NO~ \xrightarrow{k_2}~ NOBr + NOBr$