| ( | ( | 220 | + | 260 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 40 | × | 63 | = | 42147 |
| Left side of the equation = | ( | ( | 220 | + | 260 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 2520 |
| ( | ( | 220 | + | 260 | + | 260 | ) | × | 63 | − | x | ) | × | 17 20 | + | 2520 | = | 42147 |
| Left side of the equation = | ( | 220 | + | 260 | + | 260 | ) | × | 63 | × | 17 20 | − | x | × | 17 20 | + | 2520 |
| = | ( | 220 | + | 260 | + | 260 | ) | × | 1071 20 | − | x | × | 17 20 | + | 2520 |
| = | 220 | × | 1071 20 | + | 260 | × | 1071 20 | + | 260 | × | 1071 20 | − | 17 20 | x | + | 2520 |
| = | 11781 | + | 13923 | + | 13923 | − | 17 20 | x | + | 2520 |
| = | 42147 | − | 17 20 | x |
| 42147 | − | 17 20 | x | = | 42147 |
| - | 17 20 | x | = | 42147 | − | 42147 |
| - | 17 20 | x | = | 0 |
| - | 0 | = | 17 20 | x |
17 20 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 17 20 |
| = | - | 0 | × | 20 17 |
| x | = | 0 |