Note:

- A rational equation is an equation where at least one denominator
contains a variable.
- When a denominator contains a variable, there is a restriction on the
domain. The variable cannot take on any number that would cause any
denominator to be zero.
- The first step is solving a rational equation is to convert the
equation to an equation without denominators. This new equation may be
equivalent (same solutions as the original equation) or it may not be
equivalent (extraneous solutions).
- The next step is to set the equation equal to zero and solve.
- Remember that you are trying to isolate the variable.
- Depending on the problem, there are several methods available to help you solve the problem.

If you would like an in-depth review of fractions, click on Fractions.

**Solve for x in the following equation.**

**Example 3:**

Recall that you cannot divide by zero. Therefore, we must eliminate any
values of x that will cause the denominator to have a value of zero. We
determine these values by setting the denominators equal to zero and solving
for x.

The only way a product equals zero is if at least one of the factors equals
zero.

If any of the solutions turn out to be either 2, , we will discard them as extraneous solutions.

Simplify the equation by subtracting 3 from both sides of the original
equation.

Simplify the equation by getting rid of the denominators. You do this by multiplying both sides by the product of the denominators:

Rewrite the last equation in factored form.

The only way a product can equal zero is if at least one of the factors
equals zero.

Since
is not a real number, the only real
solutions is *x*=15.

Check the solution *x*=15 in the original equation for x. If the left side
of the equation equals the right side of the equation after the
substitution, you have found the correct answer.

Since the left side of the original equation is equal to the right side of
the original equation after we substitute the value 15 for x, then *x*=15is a solution.

You can also check your answer by graphing

.

(formed by subtracting the right side of the original equation from
the left side). Look to see where the graph crosses the x-axis; that will be
the real solution. Note that the graph crosses the x-axis at one place, 15.

This means that there is one real solution and the solution is *x*=15.

**
If you would like to test yourself by working some problems similar to this
example, click on Problem
**

If you would like to go back to the equation table of contents, click on
Contents

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