| ( | 542 25 | + | 2109 100 | + | 527 25 | + | x | ) | ÷ | 4 | = | 85 4 |
| 方程左边 = | 542 25 | × | 1 4 | + | 2109 100 | × | 1 4 | + | 527 25 | × | 1 4 | + | x | × | 1 4 |
| = | 271 50 | + | 2109 400 | + | 527 100 | + | x | × | 1 4 |
| = | 1277 80 | + | 1 4 | x |
1277 80 | + | 1 4 | x | = | 85 4 |
1 4 | x | = | 85 4 | − | 1277 80 |
1 4 | x | = | 423 80 |
| x | = | 423 80 | ÷ | 1 4 |
| = | 423 80 | × | 4 |
| = | 423 20 | × | 1 |
| x | = | 423 20 |
| x | = | 21.15 |