| ( | 31600 | + | 3500 | ) | + | 700 | x | = | 900 | x |
| Left side of the equation = | 31600 | + | 3500 | + | 700 | x |
| = | 35100 | + | 700 | x |
| 35100 | + | 700 | x | = | 900 | x |
| 700 | x | − | 900 | x | = | - | 35100 |
| - | 200 | x | = | - | 35100 |
| 35100 | = | 200 | x |
| 200 | x | = | 35100 |
| x | = | 35100 | ÷ | 200 |
| = | 35100 | × | 1 200 |
| = | 351 | × | 1 2 |
| x | = | 351 2 |
| x | = | 175.5 |