90 100 | ( | 30 100 | x | + | 20 100 | ( | 200 | − | x | ) | + | 200 | ) | − | 200 | = | 277 10 |
方程左边 = | 90 100 | × | 30 100 | x | + | 90 100 | × | 20 100 | ( | 200 | − | x | ) | + | 90 100 | × | 200 | − | 200 |
= | 27 100 | x | + | 9 50 | ( | 200 | − | x | ) | + | 180 | − | 200 |
= | 27 100 | x | + | 9 50 | ( | 200 | − | x | ) | − | 20 |
= | 27 100 | x | + | 9 50 | × | 200 | − | 9 50 | x | − | 20 |
= | 27 100 | x | + | 36 | − | 9 50 | x | − | 20 |
= | 9 100 | x | + | 16 |
9 100 | x | + | 16 | = | 277 10 |
9 100 | x | = | 277 10 | − | 16 |
9 100 | x | = | 117 10 |
x | = | 117 10 | ÷ | 9 100 |
= | 117 10 | × | 100 9 |
= | 13 | × | 10 |
x | = | 130 |