As FFF says: Brahma, Shiva and Vishnu are the trimurti: the three faces of God, or rather aspects of.
Brahman is indescribable: an absolute, but all tings are aspects of him / her / it.
However that's proper Brahamnistic faith- there is also village faith, a more pared down version (very patronising names I know but they were used by the Oxford Uni bloke lecturing my Uni lecturer so don;t feel quite qualified to change them)- and in village faith many see the gods as entirties as theya re. Village faith also develops new Gods- eg Santosi Ma, whom a stroy about was amde into a film in IIRC the 1960's, and then the Goddess evolved.
So that is the proper answer- depends on who is doing the believing. Oh adn whether the RE Teacher is up on fairly modern theories LOL as my world faith degree is 2008.