| ( | y | × | 2 | ÷ | 3 | ) | × | 20 | + | y | × | 30 | × | 3 | = | 1769 10 |
| 方程左边 = | ( | y | × | 2 | ÷ | 3 | ) | × | 20 | + | y | × | 90 |
| ( | y | × | 2 | ÷ | 3 | ) | × | 20 | + | 90 | y | = | 1769 10 |
| 方程左边 = | y | × | 2 | ÷ | 3 | × | 20 | + | 90 | y |
| = | y | × | 40 3 | + | 90 | y |
| = | 310 3 | y |
310 3 | y | = | 1769 10 |
| y | = | 1769 10 | ÷ | 310 3 |
| = | 1769 10 | × | 3 310 |
| y | = | 5307 3100 |
| y | = | 1.711935 |