| 20 | × | 80 | + | 20 | × | 3 4 | ( | x | − | 2 100 | x | − | 80 | ) | − | 8 | x | = | 1740 |
| Left side of the equation = | 1600 | + | 15 | ( | x | − | 2 100 | x | − | 80 | ) | − | 8 | x |
| 1600 | + | 15 | ( | x | − | 2 100 | x | − | 80 | ) | − | 8 | x | = | 1740 |
| Left side of the equation = | 1600 | + | 15 | x | − | 15 | × | 2 100 | x | − | 15 | × | 80 | − | 8 | x |
| = | 1600 | + | 15 | x | − | 3 10 | x | − | 1200 | − | 8 | x |
| = | 400 | + | 67 10 | x |
| 400 | + | 67 10 | x | = | 1740 |
67 10 | x | = | 1740 | − | 400 |
67 10 | x | = | 1340 |
| x | = | 1340 | ÷ | 67 10 |
| = | 1340 | × | 10 67 |
| = | 20 | × | 10 |
| x | = | 200 |