| ( | x | + | 30 | ) | ( | 380 | − | 2 | x | ) | + | ( | 70 | − | x | ) | × | 150 | = | 0 |
| Left side of the equation = | x | ( | 380 | − | 2 | x | ) | + | 30 | ( | 380 | − | 2 | x | ) | + | ( | 70 | − | x | ) | × | 150 |
| = | x | × | 380 | − | x | × | 2 | x | + | 30 | ( | 380 | − | 2 | x | ) | + | ( | 70 | − | x | ) | × | 150 |
| = | 380 | x | − | x | × | 2 | x | + | 30 | × | 380 | − | 30 | × | 2 | x | + | ( | 70 | − | x | ) | × | 150 |
| = | 380 | x | − | x | × | 2 | x | + | 11400 | − | 60 | x | + | ( | 70 | − | x | ) | × | 150 |
| = | 320 | x | − | x | × | 2 | x | + | 11400 | + | ( | 70 | − | x | ) | × | 150 |
| = | 320 | x | − | x | × | 2 | x | + | 11400 | + | 70 | × | 150 | − | x | × | 150 |
| = | 320 | x | − | x | × | 2 | x | + | 11400 | + | 10500 | − | x | × | 150 |
| = | 170 | x | − | x | × | 2 | x | + | 21900 |
| 170 | x | − | x | × | 2 | x | + | 21900 | = | 0 |