The plaintiffs urged the justices to intervene, saying the current system has led to large inequities. Attorneys for the state contend that school funding is "political" and that the judiciary has no role.
The justices will be asked to determine whether they should intervene. Gov. Wolf says no.
Six of the 50 most segregating borders are in Pennsylvania.
For the small part of aid driven by the calculation, the state recognizes the various burdens that educators face.