| ( | 96 | − | 64 | − | x | ) | ( | 20 | + | 4 | x | ) | = | 1200 |
| 方程左边 = | 96 | ( | 20 | + | 4 | x | ) | − | 64 | ( | 20 | + | 4 | x | ) | − | x | ( | 20 | + | 4 | x | ) |
| = | 96 | × | 20 | + | 96 | × | 4 | x | − | 64 | ( | 20 | + | 4 | x | ) | − | x | ( | 20 | + | 4 | x | ) |
| = | 1920 | + | 384 | x | − | 64 | ( | 20 | + | 4 | x | ) | − | x | ( | 20 | + | 4 | x | ) |
| = | 1920 | + | 384 | x | − | 64 | × | 20 | − | 64 | × | 4 | x | − | x | ( | 20 | + | 4 | x | ) |
| = | 1920 | + | 384 | x | − | 1280 | − | 256 | x | − | x | ( | 20 | + | 4 | x | ) |
| = | 640 | + | 128 | x | − | x | ( | 20 | + | 4 | x | ) |
| = | 640 | + | 128 | x | − | x | × | 20 | − | x | × | 4 | x |
| = | 640 | + | 108 | x | − | x | × | 4 | x |
| 640 | + | 108 | x | − | x | × | 4 | x | = | 1200 |