| ( | x | − | 300 | ) | × | 4 5 | + | 300 | = | ( | x | − | 200 | ) | × | 17 20 | + | 200 |
| Left side of the equation = | x | × | 4 5 | − | 300 | × | 4 5 | + | 300 |
| = | x | × | 4 5 | − | 240 | + | 300 |
| = | 4 5 | x | + | 60 |
4 5 | x | + | 60 | = | ( | x | − | 200 | ) | × | 17 20 | + | 200 |
| Right side of the equation = | x | × | 17 20 | − | 200 | × | 17 20 | + | 200 |
| = | x | × | 17 20 | − | 170 | + | 200 |
| = | 17 20 | x | + | 30 |
4 5 | x | + | 60 | = | 17 20 | x | + | 30 |
4 5 | x | − | 17 20 | x | = | 30 | − | 60 |
| - | 1 20 | x | = | 30 | − | 60 |
| - | 1 20 | x | = | - | 30 |
| 30 | = | 1 20 | x |
1 20 | x | = | 30 |
| x | = | 30 | ÷ | 1 20 |
| = | 30 | × | 20 |
| x | = | 600 |