( | 1 | + | 30 100 | ) | x | × | 9 1000 | + | ( | 300 | − | x | ) | × | 3 25000000 | − | 300 | = | 42 |
方程左边 = | 1 | x | × | 9 1000 | + | 30 100 | x | × | 9 1000 | + | ( | 300 | − | x | ) | × | 3 25000000 | − | 300 |
= | 9 1000 | x | + | 27 10000 | x | + | ( | 300 | − | x | ) | × | 3 25000000 | − | 300 |
= | 117 10000 | x | + | ( | 300 | − | x | ) | × | 3 25000000 | − | 300 |
= | 117 10000 | x | + | 300 | × | 3 25000000 | − | x | × | 3 25000000 | − | 300 |
= | 117 10000 | x | + | 9 250000 | − | x | × | 3 25000000 | − | 300 |