| 5 | ( | 1 | + | 3 | a | ) | × | 120 | ( | 1 | − | 2 | × | 5 100 | ) | + | 15 | ( | 1 | + | 5 | a | ) | × | 16 | ( | 1 | + | 2 | × | 5 | a | ) | = | 840 | ( | 1 | + | 2 | a | ) |
| Left side of the equation = | 600 | ( | 1 | + | 3 | a | ) | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| 600 | ( | 1 | + | 3 | a | ) | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) | = | 840 | ( | 1 | + | 2 | a | ) |
| Left side of the equation = | 600 | × | 1 | ( | 1 | − | 2 | × | 5 100 | ) | + | 600 | × | 3 | a | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 600 | ( | 1 | − | 2 | × | 5 100 | ) | + | 1800 | a | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 600 | × | 1 | − | 600 | × | 2 | × | 5 100 | + | 1800 | a | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 600 | − | 60 | + | 1800 | a | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1800 | a | ( | 1 | − | 2 | × | 5 100 | ) | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1800 | a | × | 1 | − | 1800 | a | × | 2 | × | 5 100 | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1800 | a | − | 180 | a | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1620 | a | + | 240 | ( | 1 | + | 5 | a | ) | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1620 | a | + | 240 | × | 1 | ( | 1 | + | 2 | × | 5 | a | ) | + | 240 | × | 5 | a | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1620 | a | + | 240 | ( | 1 | + | 2 | × | 5 | a | ) | + | 1200 | a | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1620 | a | + | 240 | × | 1 | + | 240 | × | 2 | × | 5 | a | + | 1200 | a | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 540 | + | 1620 | a | + | 240 | + | 2400 | a | + | 1200 | a | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 780 | + | 4020 | a | + | 1200 | a | ( | 1 | + | 2 | × | 5 | a | ) |
| = | 780 | + | 4020 | a | + | 1200 | a | × | 1 | + | 1200 | a | × | 2 | × | 5 | a |
| = | 780 | + | 4020 | a | + | 1200 | a | + | 12000 | a | a |
| = | 780 | + | 5220 | a | + | 12000 | a | a |
| 780 | + | 5220 | a | + | 12000 | a | a | = | 840 | ( | 1 | + | 2 | a | ) |
| Right side of the equation = | 840 | × | 1 | + | 840 | × | 2 | a |
| = | 840 | + | 1680 | a |
| 780 | + | 5220 | a | + | 12000 | a | a | = | 840 | + | 1680 | a |