| x | = | 400 | ( | 7 5 | − | x | ) | ÷ | 300 |
| Right side of the equation = | 4 3 | ( | 7 5 | − | x | ) |
| x | = | 4 3 | ( | 7 5 | − | x | ) |
| Right side of the equation = | 4 3 | × | 7 5 | − | 4 3 | x |
| = | 28 15 | − | 4 3 | x |
| x | = | 28 15 | − | 4 3 | x |
| x | + | 4 3 | x | = | 28 15 |
7 3 | x | = | 28 15 |
| x | = | 28 15 | ÷ | 7 3 |
| = | 28 15 | × | 3 7 |
| = | 4 5 | × | 1 |
| x | = | 4 5 |
| x | = | 0.8 |