( | 400 | − | x | ) | ( | 8 | + | 4 5 | x | ) | = | 5000 |
Left side of the equation = | 400 | ( | 8 | + | 4 5 | x | ) | − | x | ( | 8 | + | 4 5 | x | ) |
= | 400 | × | 8 | + | 400 | × | 4 5 | x | − | x | ( | 8 | + | 4 5 | x | ) |
= | 3200 | + | 320 | x | − | x | ( | 8 | + | 4 5 | x | ) |
= | 3200 | + | 320 | x | − | x | × | 8 | − | x | × | 4 5 | x |
= | 3200 | + | 312 | x | − | x | × | 4 5 | x |
3200 | + | 312 | x | − | x | × | 4 5 | x | = | 5000 |