| ( | 80 | + | x | ) | ÷ | ( | 101 | + | x | ) | = | 883 1000 |
| 方程两边同时乘以: | ( | 101 | + | x | ) |
| ( | 80 | + | x | ) | = | 883 1000 | ( | 101 | + | x | ) |
| 80 | + | x | = | 883 1000 | ( | 101 | + | x | ) |
| 80 | + | x | = | 883 1000 | × | 101 | + | 883 1000 | x |
| 80 | + | x | = | 89183 1000 | + | 883 1000 | x |
| x | − | 883 1000 | x | = | 89183 1000 | − | 80 |
117 1000 | x | = | 89183 1000 | − | 80 |
117 1000 | x | = | 9183 1000 |
| x | = | 9183 1000 | ÷ | 117 1000 |
| = | 9183 1000 | × | 1000 117 |
| = | 3061 | × | 1 39 |
| x | = | 3061 39 |
| x | = | 78.487179 |