| ( | 1 | + | 30 100 | ) | x | × | 70 100 | + | ( | 250 | − | x | ) | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 | = | 67 2 |
| Left side of the equation = | 1 | x | × | 70 100 | + | 30 100 | x | × | 70 100 | + | ( | 250 | − | x | ) | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 7 10 | x | + | 21 100 | x | + | ( | 250 | − | x | ) | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | + | ( | 250 | − | x | ) | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | + | 250 | ( | 1 | + | 20 100 | ) | × | 70 100 | − | x | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | + | 175 | ( | 1 | + | 20 100 | ) | − | x | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | + | 175 | × | 1 | + | 175 | × | 20 100 | − | x | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | + | 175 | + | 35 | − | x | ( | 1 | + | 20 100 | ) | × | 70 100 | − | 250 |
| = | 91 100 | x | − | 40 | − | x | ( | 1 | + | 20 100 | ) | × | 70 100 |
| = | 91 100 | x | − | 40 | − | x | × | 1 | × | 70 100 | − | x | × | 20 100 | × | 70 100 |
| = | 91 100 | x | − | 40 | − | x | × | 7 10 | − | x | × | 7 50 |
| = | 7 100 | x | − | 40 |
7 100 | x | − | 40 | = | 67 2 |
7 100 | x | = | 67 2 | + | 40 |
7 100 | x | = | 147 2 |
| x | = | 147 2 | ÷ | 7 100 |
| = | 147 2 | × | 100 7 |
| = | 21 | × | 50 |
| x | = | 1050 |