Complete the reactions and balance them.

(a) CuO + CO ⟶

(b) Fe₂O₃ + CO ⟶

(a) CuO + CO $\xrightarrow{\enspace\Delta\enspace}$ Cu + CO₂

(b) Fe₂O₃ + 3CO $\xrightarrow{\enspace\Delta\enspace}$ 2Fe + 3CO₂