( | 1 | + | x | ) | ( | 300 | − | 10 | x | ) | = | 1300 |
Left side of the equation = | 1 | ( | 300 | − | 10 | x | ) | + | x | ( | 300 | − | 10 | x | ) |
= | 1 | × | 300 | − | 1 | × | 10 | x | + | x | ( | 300 | − | 10 | x | ) |
= | 300 | − | 10 | x | + | x | ( | 300 | − | 10 | x | ) |
= | 300 | − | 10 | x | + | x | × | 300 | − | x | × | 10 | x |
= | 300 | + | 290 | x | − | x | × | 10 | x |
300 | + | 290 | x | − | x | × | 10 | x | = | 1300 |