( | 160 | − | 4 | x | ) | ( | 10 | + | x | ) | = | 0 |
Left side of the equation = | 160 | ( | 10 | + | x | ) | − | 4 | x | ( | 10 | + | x | ) |
= | 160 | × | 10 | + | 160 | x | − | 4 | x | ( | 10 | + | x | ) |
= | 1600 | + | 160 | x | − | 4 | x | ( | 10 | + | x | ) |
= | 1600 | + | 160 | x | − | 4 | x | × | 10 | − | 4 | x | x |
= | 1600 | + | 160 | x | − | 40 | x | − | 4 | x | x |
= | 1600 | + | 120 | x | − | 4 | x | x |
1600 | + | 120 | x | − | 4 | x | x | = | 0 |