( | 1200 | + | x | ) | × | 7 5 | × | 25 | × | 31 20 | × | 3 | = | 0 |
方程左边 = | ( | 1200 | + | x | ) | × | 651 4 |
( | 1200 | + | x | ) | × | 651 4 | = | 0 |
方程左边 = | 1200 | × | 651 4 | + | x | × | 651 4 |
= | 195300 | + | x | × | 651 4 |
195300 | + | 651 4 | x | = | 0 |
651 4 | x | = | 0 | − | 195300 |
651 4 | x | = | - | 195300 |
x | = | - | 195300 | ÷ | 651 4 |
= | - | 195300 | × | 4 651 |
= | - | 300 | × | 4 |
x | = | - | 1200 |