2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60667We consider quantum group theory on the Hilbert space level. We find all unitary representations of three braided quantum groups related to the quantum ``ax+b'' group. First we introduce an auxiliary braided quantum group, which is apparently not related to the quantum ``ax+b'' group, but easy to work with. We find all unitary representations of this quantum group. Then we use this result to find all unitary representations of another braided quantum group, whose C*-algebra is generated by two (out of three) generators generating (in the sense of Woronowicz) C*-algebra of the quantum ``ax+b''- group. We find all unitary representations of this other braided quantum group. This is the most difficult result needed to classify all unitary representations of the quantum ``ax+b'' group.31 pages LaTeX, no figuresQuantum AlgebraMathematical Physics20G42; 47B25text