Learn Hardcore Russian: Я смогу сделать домашнее задание позже.

смогу = will be able (future of ability), from perfective смочь. могу = can (present ability), from imperfective мочь. Use смогу when the ability will only be true later: Сейчас не могу, но вечером смогу.

Why is the infinitive сделать used and not делать?

сделать is perfective and focuses on completing the homework as a single whole. After смогу in a one‑time plan, perfective is natural: will be able to get it done. смогу делать would mean be able to do it as an activity or habit (e.g., on certain days), not about finishing one assignment.

Can I say Я сделаю домашнее задание позже? What’s the difference?

Both are correct but nuanced differently:

Я сделаю... позже states a plan/promise: I will do it later.
Я смогу сделать... позже highlights possibility/constraints: I cannot now, but later it becomes possible. It can sound a bit less committal or more conditional.

Why домашнее, not домашняя?