| 13 | ÷ | 4 | × | x | + | 390 | = | - | 1 | ÷ | 3 | × | x | + | 275 |
| Left side of the equation = | 13 4 | x | + | 390 |
13 4 | x | + | 390 | = | - | 1 | ÷ | 3 | × | x | + | 275 |
| Right side of the equation = | - | 1 3 | x | + | 275 |
13 4 | x | + | 390 | = | - | 1 3 | x | + | 275 |
13 4 | x | + | 1 3 | x | = | 275 | − | 390 |
43 12 | x | = | 275 | − | 390 |
43 12 | x | = | - | 115 |
| x | = | - | 115 | ÷ | 43 12 |
| = | - | 115 | × | 12 43 |
| x | = | - | 1380 43 |
| x | = | - 32.093023 |