| ( | 25 | + | 2 | y | ) | ( | 2 | y | + | 2 | y | ) | = | 888 |
| 方程左边 = | 25 | ( | 2 | y | + | 2 | y | ) | + | 2 | y | ( | 2 | y | + | 2 | y | ) |
| = | 25 | × | 2 | y | + | 25 | × | 2 | y | + | 2 | y | ( | 2 | y | + | 2 | y | ) |
| = | 50 | y | + | 50 | y | + | 2 | y | ( | 2 | y | + | 2 | y | ) |
| = | 100 | y | + | 2 | y | ( | 2 | y | + | 2 | y | ) |
| = | 100 | y | + | 2 | y | × | 2 | y | + | 2 | y | × | 2 | y |
| = | 100 | y | + | 4 | y | y | + | 4 | y | y |
| 100 | y | + | 4 | y | y | + | 4 | y | y | = | 888 |
| y1= | - | 37 2 |
| y2=6 |