| ( | 1 | + | 5 | ÷ | 8 | ) | x | = | ( | 900 | − | x | ) | ( | 1 | + | 3 | ÷ | 10 | ) |
| Left side of the equation = | 1 | x | + | 5 | ÷ | 8 | × | x |
| = | 1 | x | + | 5 8 | x |
| = | 13 8 | x |
13 8 | x | = | ( | 900 | − | x | ) | ( | 1 | + | 3 | ÷ | 10 | ) |
| Right side of the equation = | 900 | ( | 1 | + | 3 | ÷ | 10 | ) | − | x | ( | 1 | + | 3 | ÷ | 10 | ) |
| = | 900 | × | 1 | + | 900 | × | 3 | ÷ | 10 | − | x | ( | 1 | + | 3 | ÷ | 10 | ) |
| = | 900 | + | 270 | − | x | ( | 1 | + | 3 | ÷ | 10 | ) |
| = | 1170 | − | x | ( | 1 | + | 3 | ÷ | 10 | ) |
| = | 1170 | − | x | × | 1 | − | x | × | 3 | ÷ | 10 |
| = | 1170 | − | x | × | 1 | − | x | × | 3 10 |
| = | 1170 | − | 13 10 | x |
13 8 | x | = | 1170 | − | 13 10 | x |
13 8 | x | + | 13 10 | x | = | 1170 |
117 40 | x | = | 1170 |
| x | = | 1170 | ÷ | 117 40 |
| = | 1170 | × | 40 117 |
| = | 10 | × | 40 |
| x | = | 400 |