3 | ( | N | × | 129 | × | 1 5 | + | 400 | ) | = | N | × | 129 | × | 1 5 | + | 400 |
方程左边 = | 3 | N | × | 129 | × | 1 5 | + | 3 | × | 400 |
= | 387 5 | N | + | 1200 |
387 5 | N | + | 1200 | = | N | × | 129 | × | 1 5 | + | 400 |
方程右边 = | N | × | 129 5 | + | 400 |
387 5 | N | + | 1200 | = | 129 5 | N | + | 400 |
387 5 | N | − | 129 5 | N | = | 400 | − | 1200 |
258 5 | N | = | 400 | − | 1200 |
258 5 | N | = | - | 800 |
N | = | - | 800 | ÷ | 258 5 |
= | - | 800 | × | 5 258 |
= | - | 400 | × | 5 129 |
N | = | - | 2000 129 |
N | = | - 15.503876 |