| ( | 14 | − | 1 10 | a | − | 8 | ) | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) | = | 2280 |
| 方程左边 = | 14 | ( | 140 | − | 4 | a | ) | − | 1 10 | a | ( | 140 | − | 4 | a | ) | − | 8 | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 14 | × | 140 | − | 14 | × | 4 | a | − | 1 10 | a | ( | 140 | − | 4 | a | ) | − | 8 | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 1960 | − | 56 | a | − | 1 10 | a | ( | 140 | − | 4 | a | ) | − | 8 | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 1960 | − | 56 | a | − | 1 10 | a | × | 140 | + | 1 10 | a | × | 4 | a | − | 8 | ( | 140 | − | 4 | a | ) |
| = | 1960 | − | 56 | a | − | 14 | a | + | 2 5 | a | a | − | 8 | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 1960 | − | 70 | a | + | 2 5 | a | a | − | 8 | ( | 140 | − | 4 | a | ) | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 1960 | − | 70 | a | + | 2 5 | a | a | − | 8 | × | 140 | + | 8 | × | 4 | a | + | ( | 24 | − | 12 | ) |
| = | 1960 | − | 70 | a | + | 2 5 | a | a | − | 1120 | + | 32 | a | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 840 | − | 38 | a | + | 2 5 | a | a | + | ( | 24 | − | 12 | ) | ( | 120 | − | 1 2 | a | ) |
| = | 840 | − | 38 | a | + | 2 5 | a | a | + | 24 | ( | 120 | − | 1 2 | a | ) | − | 12 | ( | 120 | − | 1 2 | a | ) |
| = | 840 | − | 38 | a | + | 2 5 | a | a | + | 24 | × | 120 | − | 24 | × | 1 2 | a | − | 12 |
| = | 840 | − | 38 | a | + | 2 5 | a | a | + | 2880 | − | 12 | a | − | 12 | ( | 120 | − | 1 2 | a | ) |
| = | 3720 | − | 50 | a | + | 2 5 | a | a | − | 12 | ( | 120 | − | 1 2 | a | ) |
| = | 3720 | − | 50 | a | + | 2 5 | a | a | − | 12 | × | 120 | + | 12 | × | 1 2 | a |
| = | 3720 | − | 50 | a | + | 2 5 | a | a | − | 1440 | + | 6 | a |
| = | 2280 | − | 44 | a | + | 2 5 | a | a |
| 2280 | − | 44 | a | + | 2 5 | a | a | = | 2280 |