| ( | ( | 19 20 | + | 31 20 | ) | × | 19 20 | + | y | ) | × | 51 50 | = | 1 | + | y |
| 方程左边 = | ( | 19 20 | + | 31 20 | ) | × | 19 20 | × | 51 50 | + | y | × | 51 50 |
| = | ( | 19 20 | + | 31 20 | ) | × | 969 1000 | + | y | × | 51 50 |
| = | 19 20 | × | 969 1000 | + | 31 20 | × | 969 1000 | + | 51 50 | y |
| = | 18411 20000 | + | 30039 20000 | + | 51 50 | y |
| = | 969 400 | + | 51 50 | y |
969 400 | + | 51 50 | y | = | 1 | + | y |
51 50 | y | − | y | = | 1 | − | 969 400 |
1 50 | y | = | 1 | − | 969 400 |
1 50 | y | = | - | 569 400 |
| y | = | - | 569 400 | ÷ | 1 50 |
| = | - | 569 400 | × | 50 |
| = | - | 569 8 | × | 1 |
| y | = | - | 569 8 |
| y | = | - 71.125 |