| ( | x | − | 310 | ) | × | 3 4 | ÷ | 9100 | = | ( | x | − | 420 | ) | × | 3 4 | ÷ | 9000 |
| 方程左边 = | ( | x | − | 310 | ) | × | 3 36400 |
| ( | x | − | 310 | ) | × | 3 36400 | = | ( | x | − | 420 | ) | × | 3 4 | ÷ | 9000 |
| 方程左边 = | x | × | 3 36400 | − | 310 | × | 3 36400 |
| = | x | × | 3 36400 | − | 93 3640 |
3 36400 | x | − | 93 3640 | = | ( | x | − | 420 | ) | × | 3 4 | ÷ | 9000 |
| 方程右边 = | ( | x | − | 420 | ) | × | 1 12000 |
3 36400 | x | − | 93 3640 | = | ( | x | − | 420 | ) | × | 1 12000 |
| 方程右边 = | x | × | 1 12000 | − | 420 | × | 1 12000 |
| = | x | × | 1 12000 | − | 7 200 |
3 36400 | x | − | 93 3640 | = | 1 12000 | x | − | 7 200 |
3 36400 | x | − | 1 12000 | x | = | - | 7 200 | + | 93 3640 |
| - | 1 1092000 | x | = | - | 7 200 | + | 93 3640 |
| - | 1 1092000 | x | = | - | 43 4550 |
43 4550 | = | 1 1092000 | x |
1 1092000 | x | = | 43 4550 |
| x | = | 43 4550 | ÷ | 1 1092000 |
| = | 43 4550 | × | 1092000 |
| = | 43 | × | 240 |
| x | = | 10320 |