| 80 | X | + | 30 | X | = | 80 | X | + | 80 | × | 28 100 |
| Left side of the equation = | 110 | X |
| 110 | X | = | 80 | X | + | 80 | × | 28 100 |
| Right side of the equation = | 80 | X | + | 112 5 |
| 110 | X | = | 80 | X | + | 112 5 |
| 110 | X | − | 80 | X | = | 112 5 |
| 30 | X | = | 112 5 |
| X | = | 112 5 | ÷ | 30 |
| = | 112 5 | × | 1 30 |
| = | 56 5 | × | 1 15 |
| X | = | 56 75 |
| X | = | 0.746667 |