( | X | + | 9 | ) | ÷ | ( | X | + | 100 | ) | = | 7 20 |
Multiply both sides of the equation by: | ( | X | + | 100 | ) |
( | X | + | 9 | ) | = | 7 20 | ( | X | + | 100 | ) |
X | + | 9 | = | 7 20 | ( | X | + | 100 | ) |
X | + | 9 | = | 7 20 | X | + | 7 20 | × | 100 |
X | + | 9 | = | 7 20 | X | + | 35 |
X | − | 7 20 | X | = | 35 | − | 9 |
13 20 | X | = | 35 | − | 9 |
13 20 | X | = | 26 |
X | = | 26 | ÷ | 13 20 |
= | 26 | × | 20 13 |
= | 2 | × | 20 |
X | = | 40 |