| 420 | ÷ | 30 | × | x | + | 135 | ÷ | 30 | × | ( | x | + | 15 | ) | + | 90 | ÷ | 30 | × | ( | x | + | 30 | ) | = | 983 |
| 方程左边 = | 14 | x | + | 9 2 | ( | x | + | 15 | ) | + | 3 | ( | x | + | 30 | ) |
| 14 | x | + | 9 2 | ( | x | + | 15 | ) | + | 3 | ( | x | + | 30 | ) | = | 983 |
| 方程左边 = | 14 | x | + | 9 2 | x | + | 9 2 | × | 15 | + | 3 | ( | x | + | 30 | ) |
| = | 14 | x | + | 9 2 | x | + | 135 2 | + | 3 | ( | x | + | 30 | ) |
| = | 37 2 | x | + | 135 2 | + | 3 | ( | x | + | 30 | ) |
| = | 37 2 | x | + | 135 2 | + | 3 | x | + | 3 | × | 30 |
| = | 37 2 | x | + | 135 2 | + | 3 | x | + | 90 |
| = | 43 2 | x | + | 315 2 |
43 2 | x | + | 315 2 | = | 983 |
43 2 | x | = | 983 | − | 315 2 |
43 2 | x | = | 1651 2 |
| x | = | 1651 2 | ÷ | 43 2 |
| = | 1651 2 | × | 2 43 |
| = | 1651 | × | 1 43 |
| x | = | 1651 43 |
| x | = | 38.395349 |