| ( | y | − | 22 | ) | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) | = | 3640 |
| 方程左边 = | y | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) | − | 22 | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) |
| = | y | × | 160 | + | y | ( | 37 | − | y | ) | × | 120 | − | 22 | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) |
| = | 160 | y | + | y | × | 37 | × | 120 | − | y | y | × | 120 | − | 22 | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) |
| = | 160 | y | + | y | × | 4440 | − | y | y | × | 120 | − | 22 | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) |
| = | 4600 | y | − | y | y | × | 120 | − | 22 | ( | 160 | + | ( | 37 | − | y | ) | × | 120 | ) |
| = | 4600 | y | − | y | y | × | 120 | − | 22 | × | 160 | − | 22 | ( | 37 | − | y | ) | × | 120 |
| = | 4600 | y | − | y | y | × | 120 | − | 3520 | − | 2640 | ( | 37 | − | y | ) |
| = | 4600 | y | − | y | y | × | 120 | − | 3520 | − | 2640 | × | 37 | + | 2640 | y |
| = | 4600 | y | − | y | y | × | 120 | − | 3520 | − | 97680 | + | 2640 | y |
| = | 7240 | y | − | y | y | × | 120 | − | 101200 |
| 7240 | y | − | y | y | × | 120 | − | 101200 | = | 3640 |