Textbook Problem

Balance each chemical equation:

$\begin{array}{l}\text{a}{\text{. Al + O}}_{\text{2}}\to {\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}\hfill \\ \text{b}{\text{. NO + O}}_{\text{2}}\to {\text{NO}}_{\text{2}}\hfill \\ \text{c}{\text{. H}}_{\text{2}}{\text{+ Fe}}_{\text{2}}{\text{O}}_{\text{3}}\to {\text{Fe + H}}_{\text{2}}\text{O}\hfill \end{array}$