[en] The resonant dependence of the light combinational scattering intensity by fully-symmetric phonons in YBa₂Cu₃O_7-x for different polarization of incident and scattered light is investigated. An analysis of the resonance profiles shows that the scattering by 435 and 500 cm^-1 phonons is a typical two-band process and is determined by the diagonal terms of the electron-phonon interaction. The connection between the Fermi energy and velocity and the shape of the resonance is discussed. The resonant dependence for 335 cm^-1 phonons is quite different. The difference is ascribed to the fact that different electron transitions give the main contribution to the Raman polarizability