| ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) | = | x | x | + | 21 10 | × | 21 10 |
| Left side of the equation = | ( | 4 | ÷ | 3 | ) | x | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 4 | ÷ | 3 | × | x | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 4 3 | x | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 4 3 | x | ( | 4 | ÷ | 3 | ) | x | − | 4 3 | x | × | 21 10 | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 4 3 | x | ( | 4 | ÷ | 3 | ) | x | − | 14 5 | x | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 4 3 | x | × | 4 | ÷ | 3 | × | x | − | 14 5 | x | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 16 9 | x | x | − | 14 5 | x | − | 21 10 | ( | ( | 4 | ÷ | 3 | ) | x | − | 21 10 | ) |
| = | 16 9 | x | x | − | 14 5 | x | − | 21 10 | ( | 4 | ÷ | 3 | ) | x | + | 21 10 | × | 21 10 |
| = | 16 9 | x | x | − | 14 5 | x | − | 21 10 | ( | 4 | ÷ | 3 | ) | x | + | 441 100 |
| = | 16 9 | x | x | − | 14 5 | x | − | 21 10 | × | 4 | ÷ | 3 | × | x | + | 441 100 |
| = | 16 9 | x | x | − | 14 5 | x | − | 14 5 | x | + | 441 100 |
| = | 16 9 | x | x | − | 28 5 | x | + | 441 100 |
16 9 | x | x | − | 28 5 | x | + | 441 100 | = | x | x | + | 21 10 | × | 21 10 |
| Right side of the equation = | x | x | + | 441 100 |
16 9 | x | x | − | 28 5 | x | + | 441 100 | = | x | x | + | 441 100 |
| x2= | 36 5 |