Diketahui sistem persamaan: 1/a + 1/b + 3/c = 9 3/a + 1/b + 1/c

diketahui-sistem-persamaan-1-a-1-b-3-c-9-3-a-1-b-1-c
Diketahui sistem persamaan: 1/a + 1/b + 3/c = 9 3/a + 1/b + 1/c = 7 1/a + 3/b + 1/c = 7/3 Nilai a + b + c = … A. -21/40 B. -20/40 C. -19/40 D. -18/40 E. -17/40