1 2 | × | 200 | + | 7 10 | ( | x | − | 200 | ) | + | 1 2 | × | 200 | + | 7 10 | ( | 500 | − | x | − | 200 | ) | = | 290 |
| Left side of the equation = | 100 | + | 7 10 | ( | x | − | 200 | ) | + | 100 | + | 7 10 | ( | 500 | − | x | − | 200 | ) |
| = | 200 | + | 7 10 | ( | x | − | 200 | ) | + | 7 10 | ( | 500 | − | x | − | 200 | ) |
| 200 | + | 7 10 | ( | x | − | 200 | ) | + | 7 10 | ( | 500 | − | x | − | 200 | ) | = | 290 |
| Left side of the equation = | 200 | + | 7 10 | x | − | 7 10 | × | 200 | + | 7 10 | ( | 500 | − | x | − | 200 | ) |
| = | 200 | + | 7 10 | x | − | 140 | + | 7 10 | ( | 500 | − | x | − | 200 | ) |
| = | 60 | + | 7 10 | x | + | 7 10 | ( | 500 | − | x | − | 200 | ) |
| = | 60 | + | 7 10 | x | + | 7 10 | × | 500 | − | 7 10 | x | − | 7 10 | × | 200 |
| = | 60 | + | 7 10 | x | + | 350 | − | 7 10 | x | − | 140 |
| = | 270 | + | 0 | x |
| 270 | + | 0 | x | = | 290 |
| = | 290 | − | 270 |