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# Solving Rational Equations Worksheet, Definition, and Examples

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### Key Points about Solving Rational Equations

• Rational equations involve solving equations that contain fractions with variables.
• To solve rational equations, the first step is to eliminate the denominators by finding a common denominator.
• Rational equations are used in a variety of real-world applications, and understanding how to solve them is an important skill for anyone studying algebra or pursuing a career in a mathematical field.

## What are Rational Equations?

Solving rational equations is an important concept in algebra that involves solving equations that contain fractions. Rational equations are equations that contain rational expressions, which are expressions that involve fractions with variables. These equations can be challenging to solve, but with the right approach, they can be simplified and solved like any other algebraic equation.

To solve rational equations, the first step is to eliminate the denominators by finding a common denominator. This can be done by multiplying both sides of the equation by the least common multiple (LCM) of the denominators. Once the denominators have been eliminated, the equation can be simplified and solved for the variable. However, it is important to check the solutions to ensure that they are not extraneous.

Rational equations are used in a variety of real-world applications, such as calculating rates, proportions, and percentages. They are also used in engineering, science, and finance. Understanding how to solve rational equations is an important skill for anyone studying algebra or pursuing a career in a field that involves mathematical calculations. Solving rational equations can be easy with just a little understanding and practice.

Common Core Standard:
Return To: Home, Algebra One

## How to Solve Rational Equations

Solving rational equations is an essential skill in algebra, and it involves finding the value of the variable that makes the equation true. Here are the steps to solve rational equations:

### Identify the Rational Equation

A rational equation is an equation that contains at least one rational expression. A rational expression is a fraction where the numerator and denominator are polynomials. Identify the equation as a rational equation before proceeding to solve it.

### Simplify the Equation

Simplify the rational equation by multiplying both sides by the common denominator to eliminate the denominators. This step will result in a polynomial equation, which is easier to solve. Ensure that you simplify the equation correctly to avoid making mistakes.

### Solve the Equation

Solve the simplified equation by factoring or using the quadratic formula. If the equation is linear, isolate the variable by adding or subtracting terms from both sides of the equation. Ensure that you solve the equation correctly to avoid making mistakes.

### Verify the Solution

After finding the solution, verify that it is correct by substituting it back into the original equation. Ensure that the solution is not an extraneous solution, which is a solution that makes one or more of the denominators equal to zero. If the solution is an extraneous solution, discard it and look for another solution.

In conclusion, solving rational equations involves identifying the equation, simplifying it, solving it, and verifying the solution. It is essential to follow these steps correctly to avoid making mistakes and arrive at the correct solution.

## Rational Equations Definition

A rational equation is a type of equation that involves at least one rational expression, which is a fancy term for a fraction. Rational expressions typically contain variables in their denominators. A common way to solve rational equations is in the form:

P(x)/Q(x) = R(x)/S(x)

where P(x), Q(x), R(x), and S(x) are polynomials and x is the variable. The goal of solving a rational equation is to find the value(s) of x that make the equation true.

Rational equations can be classified into two types: linear and quadratic. Linear rational equations have a degree of 1 in both the numerator and denominator, while quadratic rational equations have a degree of 2 or more in either the numerator or denominator.

It is important to note that some values of x may make the denominator of a rational expression equal to zero, resulting in an undefined value. These values are called restrictions and must be excluded from the solution set of the equation.

Solving rational equations involves eliminating the denominators and simplifying the resulting expression. This is typically done by finding the least common multiple (LCM) of the denominators and multiplying both sides of the equation by the LCM. The resulting equation is then simplified to obtain the solution set.

Overall, rational equations are important in various fields of mathematics, including algebra, calculus, and differential equations. They are also used in real-world applications such as physics, engineering, and finance.

## Rational Equations Examples

Rational equations are equations that contain rational expressions. They are solved by finding the values of the variables that make the equation true. Rational equations can be solved using different methods depending on the situation. In this section, we will discuss three methods for solving rational equations: cross multiplication, factoring, and using common denominators.

### Cross Multiplication

Cross multiplication is a method used to solve rational equations that involve fractions. It involves multiplying both sides of the equation by the denominators of the fractions. For example, consider the equation:

5/x + 2/y = 3

To solve this equation using cross multiplication, we first multiply both sides by xy:

5y + 2x = 3xy

Then, we simplify the equation by moving all the terms to one side:

3xy – 5y – 2x = 0

Finally, we factor the equation and solve for x and y:

(3x – 1)(y – 5) = 0

This gives us two solutions: x = 1/3 and y = 5.

### Factoring

Factoring is another method used to solve rational equations. It involves factoring the numerator and denominator of the rational expression and canceling out common factors. For example, consider the equation:

(x + 1)/(x – 2) = (x – 3)/(x + 4)

To solve this equation using factoring, we first cross multiply to get:

(x + 1)(x + 4) = (x – 2)(x – 3)

Then, we expand the equation and simplify:

x^2 + 5x + 4 = x^2 – 5x + 6

Next, we move all the terms to one side:

10x = 2

Finally, we solve for x:

x = 1/5

### Using Common Denominators

Using common denominators is another method used to solve rational equations. It involves finding a common denominator for the rational expressions and then combining them into a single fraction. For example, consider the equation:

1/x + 1/(x + 3) = 1/(x + 6)

To solve this equation using common denominators, we first find the LCD, which is (x)(x + 3)(x + 6). Then, we multiply both sides of the equation by the LCD:

(x + 3)(x + 6) + x(x + 6) = x(x + 3)

Next, we simplify the equation:

2x^2 + 15x + 18 = 0

Finally, we solve for x:

x = -3 or x = -3/2

In summary, rational equations can be solved using different methods depending on the situation. Cross multiplication, factoring, and using common denominators are three methods that can be used to solve rational equations.

## Rational Equations Word Problems

Rational equations are equations that involve fractions with variables in the denominators. They can be used to solve a variety of real-world problems, including those involving rates, work, and mixture. In this section, we will explore some common word problems that can be solved using rational equations.

### Example 1: Pool Filling

Suppose there are two hoses, A and B, that can fill a pool. Hose A can fill the pool in 4 hours, while hose B can fill the pool in 6 hours. How long will it take to fill the pool if both hoses are used simultaneously?

To solve this problem, we can use the following equation:

1/4 + 1/6 = 1/x

Where x is the time it takes to fill the pool with both hoses. Simplifying the equation, we get:

3/12 + 2/12 = 1/x

5/12 = 1/x

x = 12/5 = 2.4

Therefore, it will take 2.4 hours, or 2 hours and 24 minutes, to fill the pool with both hoses.

### Example 2: Work Together

Suppose that Alice can paint a house in 8 hours, and Bob can paint the same house in 6 hours. How long will it take if they work together?

To solve this problem, we can use the following equation:

1/8 + 1/6 = 1/x

Where x is the time it takes to paint the house if they work together. Simplifying the equation, we get:

3/24 + 4/24 = 1/x

7/24 = 1/x

x = 24/7 = 3.43

Therefore, it will take approximately 3 hours and 26 minutes for Alice and Bob to paint the house if they work together.

### Example 3: Mixture

Suppose that a chemist has a solution that is 20% acid and another solution that is 50% acid. How many liters of each solution should be mixed to obtain 10 liters of a solution that is 30% acid?

To solve this problem, we can use the following equation:

0.2x + 0.5y = 0.3(10)

Where x is the number of liters of the 20% acid solution, and y is the number of liters of the 50% acid solution. Simplifying the equation, we get:

0.2x + 0.5y = 3

We also know that x + y = 10. Solving for x in terms of y, we get:

x = 10 – y

Substituting this into the first equation, we get:

0.2(10 – y) + 0.5y = 3

2 – 0.2y + 0.5y = 3

0.3y = 1

y = 3.33

Therefore, we need 3.33 liters of the 50% acid solution and 6.67 liters of the 20% acid solution to obtain 10 liters of a solution that is 30% acid.

## Graphing Rational Equations

Graphing rational equations can help visualize the behavior of the function and identify key features such as asymptotes and intercepts. The following steps can be used to graph a rational equation:

1. Determine the y-intercept: To find the y-intercept, set x to zero and solve for y. The resulting point is the y-intercept.
2. Determine the x-intercepts: To find the x-intercepts, set the numerator equal to zero and solve for x. The resulting points are the x-intercepts.
3. Determine the behavior at positive/negative infinity: As x approaches positive or negative infinity, the function may approach a horizontal asymptote, a vertical asymptote, or neither. To determine the behavior, divide the numerator and denominator by the highest power of x, and then take the limit as x approaches infinity or negative infinity.
4. Find any vertical asymptotes: Vertical asymptotes occur when the denominator equals zero. To find vertical asymptotes, set the denominator equal to zero and solve for x. The resulting values are the vertical asymptotes. Determine the behavior of the function around the asymptote by analyzing the sign of the numerator as x approaches the asymptote from both sides.
5. Sketch the graph: Use the information gathered from the previous steps to sketch the graph of the rational equation.

It is important to note that not all rational equations have intercepts or asymptotes. Additionally, some rational equations may have holes in the graph where the function is undefined.

Overall, graphing rational equations can provide valuable insight into the behavior of the function and help identify key features such as intercepts and asymptotes.

## Solving Rational Equations FAQ

### What are the steps to solve a rational equation?

To solve a rational equation, one should follow these steps:

• Find the common denominator of all the fractions in the equation
• Multiply both sides of the equation by the common denominator to eliminate the fractions
• Simplify the resulting equation and solve for the variable

### What are two methods to solve rational equations?

The two methods to solve rational equations are:

• Cross-multiplication method: Multiply both sides of the equation by the product of the denominators of all the fractions in the equation
• Common denominator method: Find the common denominator of all the fractions in the equation and multiply both sides of the equation by it

### What is the formula for a rational function?

The formula for a rational function is:

f(x) = p(x) / q(x)

where p(x) and q(x) are polynomials and q(x) is not equal to zero.

### What are some examples of rational equations?

Some examples of rational equations are:

• (x + 3) / (x – 2) = 4
• (2x – 1) / (x + 5) = 3
• (3x + 2) / (x – 1) + 1 = (x + 3) / (x – 1)

### How to solve rational equations with extraneous solutions?

To solve rational equations with extraneous solutions, one should:

• Check the solutions obtained by substituting them back into the original equation
• Eliminate any solutions that make the denominator zero or result in an undefined value

### What is rational equation vs expression?

A rational equation is an equation that contains one or more rational expressions. A rational expression is a fraction where the numerator and denominator are polynomials.

### What is a rational equation example?

An example of a rational equation is:

(2x – 3) / (x + 1) = (x – 4) / (x – 2)

### How do you solve rational equation?

To solve a rational equation, one should follow the steps mentioned above in the answer to the first question.

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