In this paper we prove a relative trace formula for all pairs of connected algebraic groups
, with
a reductive
group and
the direct product of a reductive group and a unipotent group, given that the test
function satisfies simplifying hypotheses. As an application, we prove a relative
analogue of the Weyl law, giving an asymptotic formula for the number of
eigenfunctions of the Laplacian on a locally symmetric space associated to
weighted by
their
-restriction
norm over a locally symmetric subspace associated to
.