A discussion on the state budget and its effect on Lexington will take place at 9:30 a.m. Friday in Cary Memorial Library. Part of a monthly series of free forums hosted by the League of Women Voters of Lexington, the program will feature Luc Schuster, a senior policy analyst for the Massachusetts Budget and Policy Center, who will show how past tax policy choices have contributed to the state’s ongoing fiscal crisis and resulting budget cuts. He will also discuss how the decisions affect school funding for communities. He will be joined by state Senators Michael Barrett of Lexington and Ken Donnelly of Arlington, and state Representative Jay Kaufman of Lexington; the Democratic lawmakers will be talking about ways the state could improve its revenue system. Coffee will be available beginning at 9:15 a.m.