| ( | 11 | − | 10 | ) | × | 400 | + | ( | 23 2 | − | 10 | ) | × | 200 | − | ( | 12 | − | y | ) | × | 500 | = | 600 |
| 方程左边 = | 11 | × | 400 | − | 10 | × | 400 | + | ( | 23 2 | − | 10 | ) | × | 200 | − | ( | 12 | − | y | ) | × | 500 |
| = | 4400 | − | 4000 | + | ( | 23 2 | − | 10 | ) | × | 200 | − | ( | 12 | − | y | ) | × | 500 |
| = | 400 | + | ( | 23 2 | − | 10 | ) | × | 200 | − | ( | 12 | − | y | ) | × | 500 |
| = | 400 | + | 23 2 | × | 200 | − | 10 | × | 200 | − | ( | 12 | − | y | ) | × | 500 |
| = | 400 | + | 2300 | − | 2000 | − | ( | 12 | − | y | ) | × | 500 |
| = | 700 | − | ( | 12 | − | y | ) | × | 500 |
| = | 700 | − | 12 | × | 500 | + | y | × | 500 |
| = | 700 | − | 6000 | + | y | × | 500 |
| = | - | 5300 | + | 500 | y |
| - | 5300 | + | 500 | y | = | 600 |
| 500 | y | = | 600 | + | 5300 |
| 500 | y | = | 5900 |
| y | = | 5900 | ÷ | 500 |
| = | 5900 | × | 1 500 |
| = | 59 | × | 1 5 |
| y | = | 59 5 |
| y | = | 11.8 |