Answer: See attached table
Explanation:
+---+---+---+
| 1 | 8 | 2 |
+---+---+---+
| 6 | 4 | 2 |
+---+---+---+
| 5 | 0 | 7 |
+---+---+---+
Proofs:
First row: 1+6+5 = 12
Second row: 8+4+0 = 12
Third row: 2+2+7 = 12
First column: 1+8+2 = 12
Second column: 6+4+2 = 12
Third column: 5+0+7 = 12
Diagonal starting from top left to bottom right: 1+4+7 = 12
Diagonal staring from top right to bottom left: 2+4+5 = 12