По свойствам площадей $$S_{ACH} + S_{CBH} = S_{ABH}$$, $$S_{ACH} = S_{ABH} - S_{CBH}$$
$$S_{ABH} = \frac{1}{2} \cdot AB \cdot h$$
$$S_{ACH} + S_{CBH} = S_{ABH}$$, $$S_{ABH} = \frac{1}{2}$$
Ответ: $$S_{ACH} + S_{CBH} = S_{ABH}$$, $$S_{ABH} = \frac{1}{2}$$