| ( | 3 | ÷ | 31 | ) | × | 19 400 | + | ( | 28 | ÷ | 31 | ) | ( | a | × | 19 400 | + | ( | 1 | − | a | ) | × | 9 200 | ) | = | 229 5000 |
| 方程左边 = | 3 | ÷ | 31 | × | 19 400 | + | ( | 28 | ÷ | 31 | ) | ( | a | × | 19 400 | + | ( | 1 | − | a | ) | × | 9 200 | ) |
| = | 57 12400 | + | ( | 28 | ÷ | 31 | ) | ( | a | × | 19 400 | + | ( | 1 | − | a | ) | × | 9 200 | ) |
| = | 57 12400 | + | 28 | ÷ | 31 | × | ( | a | × | 19 400 | + | ( | 1 | − | a | ) | × | 9 200 | ) |
| = | 57 12400 | + | 28 31 | ( | a | × | 19 400 | + | ( | 1 | − | a | ) | × | 9 200 | ) |
| = | 57 12400 | + | 28 31 | a | × | 19 400 | + | 28 31 | ( | 1 | − | a | ) | × | 9 200 |
| = | 57 12400 | + | 133 3100 | a | + | 63 1550 | ( | 1 | − | a | ) |
| = | 57 12400 | + | 133 3100 | a | + | 63 1550 | × | 1 | − | 63 1550 | a |
| = | 57 12400 | + | 133 3100 | a | + | 63 1550 | − | 63 1550 | a |
| = | 561 12400 | + | 7 3100 | a |
561 12400 | + | 7 3100 | a | = | 229 5000 |
7 3100 | a | = | 229 5000 | − | 561 12400 |
7 3100 | a | = | 173 310000 |
| a | = | 173 310000 | ÷ | 7 3100 |
| = | 173 310000 | × | 3100 7 |
| = | 173 100 | × | 1 7 |
| a | = | 173 700 |
| a | = | 0.247143 |