What if the equation of lead shot, and X is hidden in the denominator? We need to get rid of the denominator. What will happen with X? Do not worry. If you do everything correctly, he from the denominator goes into the numerator. Here you can recommend two ways to solve the equation.
The first method is to bring the expression to normal proportions. Then we use the proportion of the property  the multiplication of extreme terms in proportion equal to the multiplication of the average proportion of members. Denominator magically disappear. We get a simple equation, which can be easily solved. Consider an example.

The equation a fraction 
The number did not work nicely. Make checks and look at the result. Substitute the original expression instead of X its value.

Checking equation 
The audit showed that the equation is solved correctly.
The second method is to bring the expression to a common denominator. The denominator should be common to the left and right sides of the equation. In this case, we in good conscience can throw the denominator in the trash. We see an example of reduction to a common denominator.

The equation a fraction 
The result was the same as in the first case.