| ( | ( | ( | 3 | ÷ | 10 | ) | x | + | 50 | ) | + | ( | ( | 3 | ÷ | 4 | ) | x | − | 200 | ) | ) | = | x |
| 方程左边 = | ( | ( | 3 | ÷ | 10 | ) | x | + | 50 | ) | + | ( | ( | 3 | ÷ | 4 | ) | x | − | 200 | ) |
| = | ( | 3 | ÷ | 10 | ) | x | + | 50 | + | ( | ( | 3 | ÷ | 4 | ) | x | − | 200 | ) |
| = | 3 | ÷ | 10 | × | x | + | 50 | + | ( | ( | 3 | ÷ | 4 | ) | x | − | 200 | ) |
| = | 3 10 | x | + | 50 | + | ( | ( | 3 | ÷ | 4 | ) | x | − | 200 | ) |
| = | 3 10 | x | + | 50 | + | ( | 3 | ÷ | 4 | ) | x | − | 200 |
| = | 3 10 | x | − | 150 | + | ( | 3 | ÷ | 4 | ) | x |
| = | 3 10 | x | − | 150 | + | 3 | ÷ | 4 | × | x |
| = | 3 10 | x | − | 150 | + | 3 4 | x |
| = | 21 20 | x | − | 150 |
21 20 | x | − | 150 | = | x |
21 20 | x | − | x | = | 150 |
1 20 | x | = | 150 |
| x | = | 150 | ÷ | 1 20 |
| = | 150 | × | 20 |
| x | = | 3000 |