( | 70 100 | x | − | ( | x | − | 45 | ) | ) | x | × | 10 | = | ( | x | − | 25 | − | ( | x | − | 45 | ) | ) | x | × | 12 |
方程左边 = | 70 100 | x | x | × | 10 | − | ( | x | − | 45 | ) | x | × | 10 |
= | 7 | x | x | − | ( | x | − | 45 | ) | x | × | 10 |
= | 7 | x | x | − | x | x | × | 10 | + | 45 | x | × | 10 |
= | 7 | x | x | − | x | x | × | 10 | + | 450 | x |
7 | x | x | − | x | x | × | 10 | + | 450 | x | = | ( | x | − | 25 | − | ( | x | − | 45 | ) | ) | x | × | 12 |
方程右边 = | x | x | × | 12 | − | 25 | x | × | 12 | − | ( | x | − | 45 | ) | x | × | 12 |
= | x | x | × | 12 | − | 300 | x | − | ( | x | − | 45 | ) | x | × | 12 |
= | x | x | × | 12 | − | 300 | x | − | x | x | × | 12 | + | 45 | x | × | 12 |
= | x | x | × | 12 | − | 300 | x | − | x | x | × | 12 | + | 540 | x |
= | x | x | × | 12 | + | 240 | x | − | x | x | × | 12 |
7 | x | x | − | x | x | × | 10 | + | 450 | x | = | x | x | × | 12 | + | 240 | x | − | x | x | × | 12 |