| 70 | ÷ | 80 | = | x | ÷ | ( | x | + | 50 | ) |
| Multiply both sides of the equation by: | ( | x | + | 50 | ) |
| 70 | ÷ | 80 | × | ( | x | + | 50 | ) | = | x |
| 70 | ÷ | 80 | × | x | + | 70 | ÷ | 80 | × | 50 | = | x |
7 8 | x | + | 175 4 | = | x |
7 8 | x | − | x | = | - | 175 4 |
| - | 1 8 | x | = | - | 175 4 |
175 4 | = | 1 8 | x |
1 8 | x | = | 175 4 |
| x | = | 175 4 | ÷ | 1 8 |
| = | 175 4 | × | 8 |
| = | 175 | × | 2 |
| x | = | 350 |