| 90 | x | + | 1000 | ( | 1 | − | x | ) | = | 115 |
| Left side of the equation = | 90 | x | + | 1000 | × | 1 | − | 1000 | x |
| = | 90 | x | + | 1000 | − | 1000 | x |
| = | - | 910 | x | + | 1000 |
| - | 910 | x | + | 1000 | = | 115 |
| - | 910 | x | = | 115 | − | 1000 |
| - | 910 | x | = | - | 885 |
| 885 | = | 910 | x |
| 910 | x | = | 885 |
| x | = | 885 | ÷ | 910 |
| = | 885 | × | 1 910 |
| = | 177 | × | 1 182 |
| x | = | 177 182 |
| x | = | 0.972527 |