'Unable' in the Bible

The following are those who came from Tel-melah, Tel-harsha, Cherub, Addan, and Immer but were unable to prove that their families and ancestry were Israelite:

People were unable to tell the difference between the sound of joyous shouting and the sound of the people's weeping, for the people were shouting so loudly that the sound was heard a long way off.

However, the people are numerous and it is the rainy season. We are unable to stand here outside. Furthermore, this business cannot be resolved in a day or two, for we have sinned greatly in this matter.