| ( | 30 | + | 7 | m | ) | × | 180 | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) | = | 18720 |
| 方程左边 = | 30 | × | 180 | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | 7 | m | × | 180 | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 5400 | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | 1260 | m | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 5400 | × | 9 5 | ( | 1 | − | 1 10 | m | ) | + | 1260 | m | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | ( | 1 | − | 1 10 | m | ) | + | 1260 | m | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | × | 1 | − | 9720 | × | 1 10 | m | + | 1260 | m | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | − | 972 | m | + | 1260 | m | ( | 9 5 | ( | 1 | − | 1 10 | m | ) | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | − | 972 | m | + | 1260 | m | × | 9 5 | ( | 1 | − | 1 10 | m | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | − | 972 | m | + | 2268 | m | ( | 1 | − | 1 10 | m | ) | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | − | 972 | m | + | 2268 | m | × | 1 | − | 2268 | m | × | 1 10 | m | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 |
| = | 9720 | − | 972 | m | + | 2268 | m | − | 1134 5 | m | m | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | ( | 80 | − | ( | 30 | + | 7 | m | ) | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 80 | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 9600 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 9600 | × | 3 2 | ( | 1 | − | 1 20 | m | ) | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 14400 | ( | 1 | − | 1 20 | m | ) | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 14400 | × | 1 | − | 14400 | × | 1 20 | m | − | ( | 30 | + | 7 | m | ) |
| = | 9720 | + | 1296 | m | − | 1134 5 | m | m | + | 14400 | − | 720 | m | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | ( | 30 | + | 7 | m | ) | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 30 | × | 120 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) | − | 7 | m | × | 120 |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 3600 | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) | − | 840 | m | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 3600 | × | 3 2 | ( | 1 | − | 1 20 | m | ) | − | 840 | m | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 5400 | ( | 1 | − | 1 20 | m | ) | − | 840 | m | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 5400 | × | 1 | + | 5400 | × | 1 20 | m | − | 840 |
| = | 24120 | + | 576 | m | − | 1134 5 | m | m | − | 5400 | + | 270 | m | − | 840 | m | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| = | 18720 | + | 846 | m | − | 1134 5 | m | m | − | 840 | m | ( | 3 2 | ( | 1 | − | 1 20 | m | ) | ) |
| m1=0 |