Please show/explain all steps!

The reaction of H2 and Br2 to form HBr occurs through the following sequence of elementary steps involving free radicals: Br+H2k1k1HBr+HH+Br2k2HBr+BrBr2K32Br Use the fact that bromine radicals are in equilibrium with Br2 to derive a rate expression of the form: r=1+2([Br2][HBr])1[Br2]1/2[H2] The reaction of H2 and Br2 to form HBr occurs through the following sequence of elementary steps involving free radicals: Br+H2k1k1HBr+HH+Br2k2HBr+BrBr2K32Br Use the fact that bromine radicals are in equilibrium with Br2 to derive a rate expression of the form: r=1+2([Br2][HBr])1[Br2]1/2[H2]