  We develop a non-parametric inverse method to investigate the star formation
rate, the metallicity evolution and the reddening properties of galaxies based
on their spectral energy distributions (SEDs). This approach allows us to
clarify the level of information present in the data, depending on its
signal-to-noise ratio (S/N). When low resolution SEDs are available in the
ultraviolet, optical and near-IR wavelength ranges together, we conclude that
it is possible to constrain the star formation rate and the effective dust
optical depth simultaneously with a signal-to-noise ratio of 25. With excellent
signal-to-noise ratios, the age-metallicity relation can also be constrained.
We apply this method to the well-known nuclear starburst in the interacting
galaxy NGC 7714. We focus on deriving the SFR and the reddening law. We confirm
that classical extinction models cannot provide an acceptable simultaneous fit
of the SED and the lines. We also confirm that, with the adopted population
synthesis models and in addition to the current starburst, an episode of
enhanced star formation that started more than 200 Myr ago is required. As the
time elapsed since the last interaction with NGC 7715, based on dynamical
studies, is about 100 Myr, our result reinforces the suggestion that this
interaction might not have been the most important event in the life of NGC
7714.
