( | P | − | 700 | ) | × | 20000 | − | 400000 | = | 400000 | − | P | × | 20000 |
方程左边 = | P | × | 20000 | − | 700 | × | 20000 | − | 400000 |
= | P | × | 20000 | − | 14000000 | − | 400000 |
= | 20000 | P | − | 14400000 |
20000 | P | − | 14400000 | = | 400000 | − | P | × | 20000 |
20000 | P | + | 20000 | P | = | 400000 | + | 14400000 |
40000 | P | = | 400000 | + | 14400000 |
40000 | P | = | 14800000 |
P | = | 14800000 | ÷ | 40000 |
= | 14800000 | × | 1 40000 |
= | 370 | × | 1 |
P | = | 370 |