| ( | 240 | + | 1 5 | x | ) | ( | 1160 | + | 1 5 | x | ) | = | 0 |
| Left side of the equation = | 240 | ( | 1160 | + | 1 5 | x | ) | + | 1 5 | x | ( | 1160 | + | 1 5 | x | ) |
| = | 240 | × | 1160 | + | 240 | × | 1 5 | x | + | 1 5 | x | ( | 1160 | + | 1 5 | x | ) |
| = | 278400 | + | 48 | x | + | 1 5 | x | ( | 1160 | + | 1 5 | x | ) |
| = | 278400 | + | 48 | x | + | 1 5 | x | × | 1160 | + | 1 5 | x | × | 1 5 | x |
| = | 278400 | + | 48 | x | + | 232 | x | + | 1 25 | x | x |
| = | 278400 | + | 280 | x | + | 1 25 | x | x |
| 278400 | + | 280 | x | + | 1 25 | x | x | = | 0 |
| ( | 980 | − | 1 5 | x | ) | ( | 720 | − | 1 5 | x | ) | = | 0 |
| Left side of the equation = | 980 | ( | 720 | − | 1 5 | x | ) | − | 1 5 | x | ( | 720 | − | 1 5 | x | ) |
| = | 980 | × | 720 | − | 980 | × | 1 5 | x | − | 1 5 | x | ( | 720 | − | 1 5 | x | ) |
| = | 705600 | − | 196 | x | − | 1 5 | x | ( | 720 | − | 1 5 | x | ) |
| = | 705600 | − | 196 | x | − | 1 5 | x | × | 720 | + | 1 5 | x | × | 1 5 | x |
| = | 705600 | − | 196 | x | − | 144 | x | + | 1 25 | x | x |
| = | 705600 | − | 340 | x | + | 1 25 | x | x |
| 705600 | − | 340 | x | + | 1 25 | x | x | = | 0 |