( | 50 | − | x | ) | ( | 50 | + | 5 | x | ) | = | 4000 |
Left side of the equation = | 50 | ( | 50 | + | 5 | x | ) | − | x | ( | 50 | + | 5 | x | ) |
= | 50 | × | 50 | + | 50 | × | 5 | x | − | x | ( | 50 | + | 5 | x | ) |
= | 2500 | + | 250 | x | − | x | ( | 50 | + | 5 | x | ) |
= | 2500 | + | 250 | x | − | x | × | 50 | − | x | × | 5 | x |
= | 2500 | + | 200 | x | − | x | × | 5 | x |
2500 | + | 200 | x | − | x | × | 5 | x | = | 4000 |