  Semileptonic and nonleptonic decays of the B_c meson are studied in the
framework of the relativistic quark model. The heavy quark expansion in inverse
powers of the heavy (b,c) quark mass is used to simplify calculations while the
light final quarks in the B and D mesons are treated relativistically. The
decay form factors are explicitly expressed through the overlap integrals of
the meson wave functions in the whole accessible kinematical range. The
obtained results are compared with the predictions of other approaches.
