PENGARUH CAPITAL ADEQUACY RATIO (CAR), NON PERFORMING LOAN (NPL), BIAYA OPERASIONAL DAN PENDAPATAN OPERASIONAL (BOPO ) DAN LOAN TO DEPOSIT RATIO (LDR) TERHADAP RETURN ON ASSETS (ROA) PADA PERUSAHAAN PERBANKAN PERIODE TAHUN 2012-2014 (Students' Journal of Economic and Management, 2017)