| ( | 213 80 | x | + | 100 | ) | ( | x | + | 100 | ) | × | 2 5 | × | 7850 | = | 810000000 |
| 方程左边 = | ( | 213 80 | x | + | 100 | ) | ( | x | + | 100 | ) | × | 3140 |
| ( | 213 80 | x | + | 100 | ) | ( | x | + | 100 | ) | × | 3140 | = | 810000000 |
| 方程左边 = | 213 80 | x | ( | x | + | 100 | ) | × | 3140 | + | 100 | ( | x | + | 100 | ) | × | 3140 |
| = | 33441 4 | x | ( | x | + | 100 | ) | + | 314000 | ( | x | + | 100 | ) |
| = | 33441 4 | x | x | + | 33441 4 | x | × | 100 | + | 314000 | ( | x | + | 100 | ) |
| = | 33441 4 | x | x | + | 836025 | x | + | 314000 | ( | x | + | 100 | ) |
| = | 33441 4 | x | x | + | 836025 | x | + | 314000 | x | + | 314000 | × | 100 |
| = | 33441 4 | x | x | + | 836025 | x | + | 314000 | x | + | 31400000 |
| = | 33441 4 | x | x | + | 1150025 | x | + | 31400000 |
33441 4 | x | x | + | 1150025 | x | + | 31400000 | = | 810000000 |