| 4200 | × | 3 20 | ( | x | + | 7 10 | ) | + | 700 | ( | 3 10 | − | x | ) | + | 1600 | x | + | 30000 | × | 7 10 | = | 16000 | ( | 3 20 | x | + | 3 20 | × | 7 10 | + | 1 | ) |
| Left side of the equation = | 630 | ( | x | + | 7 10 | ) | + | 700 | ( | 3 10 | − | x | ) | + | 1600 | x | + | 21000 |
| 630 | ( | x | + | 7 10 | ) | + | 700 | ( | 3 10 | − | x | ) | + | 1600 | x | + | 21000 | = | 16000 | ( | 3 20 | x | + | 3 20 | × | 7 10 | + | 1 | ) |
| Left side of the equation = | 630 | x | + | 630 | × | 7 10 | + | 700 | ( | 3 10 | − | x | ) | + | 1600 | x | + | 21000 |
| = | 630 | x | + | 441 | + | 700 | ( | 3 10 | − | x | ) | + | 1600 | x | + | 21000 |
| = | 2230 | x | + | 21441 | + | 700 | ( | 3 10 | − | x | ) |
| = | 2230 | x | + | 21441 | + | 700 | × | 3 10 | − | 700 | x |
| = | 2230 | x | + | 21441 | + | 210 | − | 700 | x |
| = | 1530 | x | + | 21651 |
| 1530 | x | + | 21651 | = | 16000 | ( | 3 20 | x | + | 3 20 | × | 7 10 | + | 1 | ) |
| Right side of the equation = | 16000 | × | 3 20 | x | + | 16000 | × | 3 20 | × | 7 10 | + | 16000 | × | 1 |
| = | 2400 | x | + | 1680 | + | 16000 |
| = | 2400 | x | + | 17680 |
| 1530 | x | + | 21651 | = | 2400 | x | + | 17680 |
| 1530 | x | − | 2400 | x | = | 17680 | − | 21651 |
| - | 870 | x | = | 17680 | − | 21651 |
| - | 870 | x | = | - | 3971 |
| 3971 | = | 870 | x |
| 870 | x | = | 3971 |
| x | = | 3971 | ÷ | 870 |
| = | 3971 | × | 1 870 |
| x | = | 3971 870 |
| x | = | 4.564368 |