( | 400 | − | x | ) | x | ( | 8 | + | 4 | x | ) | = | 0 |
Left side of the equation = | 400 | x | ( | 8 | + | 4 | x | ) | − | x | x | ( | 8 | + | 4 | x | ) |
= | 400 | x | × | 8 | + | 400 | x | × | 4 | x | − | x | x | ( | 8 | + | 4 | x | ) |
= | 3200 | x | + | 1600 | x | x | − | x | x | ( | 8 | + | 4 | x | ) |
= | 3200 | x | + | 1600 | x | x | − | x | x | × | 8 | − | x | x | × | 4 | x |
3200 | x | + | 1600 | x | x | − | x | x | × | 8 | − | x | x | × | 4 | x | = | 0 |