In this post, I’m going to go through some of the ways we can solve a rational equation.

The first method to check is cross multiplication. This method is easier, but the only time it can be done is when there are two fractions separated by an equals sign. If the equation has more than two terms cross multiplication does not apply.

Cross multiplication is pretty self-explanatory. Here’s an example

 

This is a simple equation, but the basic principles remain the same with polynomial fractions.

Another method of solving is multiplying by a common denominator. This method can be used in any rational equation and will always result in an answer. Here’s an example of using this method to solve an equation. 

Again, we have to find the non-permissible value, and in this case, it is just a matter of looking at the denominators of the equation. If Q=2 then the denominator would become 0. This is the same with the other fraction, making the non-permissible values of Q -4 and +2.