| ( | 1 | − | 1 25 | ) | × | 400 | ( | x | − | 4 | ) | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) | = | 2984 |
| 方程左边 = | 1 | × | 400 | ( | x | − | 4 | ) | − | 1 25 | × | 400 | ( | x | − | 4 | ) | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 400 | ( | x | − | 4 | ) | − | 16 | ( | x | − | 4 | ) | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 400 | x | − | 400 | × | 4 | − | 16 | ( | x | − | 4 | ) | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 400 | x | − | 1600 | − | 16 | ( | x | − | 4 | ) | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 400 | x | − | 1600 | − | 16 | x | + | 16 | × | 4 | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 400 | x | − | 1600 | − | 16 | x | + | 64 | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 384 | x | − | 1536 | + | ( | 1 | − | 3 50 | ) | × | 800 | ( | x | − | 7 2 | ) |
| = | 384 | x | − | 1536 | + | 1 | × | 800 | ( | x | − | 7 2 | ) | − | 3 50 | × | 800 | ( | x | − | 7 2 | ) |
| = | 384 | x | − | 1536 | + | 800 | ( | x | − | 7 2 | ) | − | 48 | ( | x | − | 7 2 | ) |
| = | 384 | x | − | 1536 | + | 800 | x | − | 800 | × | 7 2 | − | 48 | ( | x | − | 7 2 | ) |
| = | 384 | x | − | 1536 | + | 800 | x | − | 2800 | − | 48 | ( | x | − | 7 2 | ) |
| = | 1184 | x | − | 4336 | − | 48 | ( | x | − | 7 2 | ) |
| = | 1184 | x | − | 4336 | − | 48 | x | + | 48 | × | 7 2 |
| = | 1184 | x | − | 4336 | − | 48 | x | + | 168 |
| = | 1136 | x | − | 4168 |
| 1136 | x | − | 4168 | = | 2984 |
| 1136 | x | = | 2984 | + | 4168 |
| 1136 | x | = | 7152 |
| x | = | 7152 | ÷ | 1136 |
| = | 7152 | × | 1 1136 |
| = | 447 | × | 1 71 |
| x | = | 447 71 |
| x | = | 6.295775 |