# Adding and Subtracting Rational Expressions With Unlike Denominators | Summary and Q&A

1.1M views
January 23, 2018
by
The Organic Chemistry Tutor
Adding and Subtracting Rational Expressions With Unlike Denominators

## TL;DR

Learn how to combine rational expressions with different denominators by finding common denominators and simplifying the expressions.

## Install to Summarize YouTube Videos and Get Transcripts

### Q: How do you add or subtract rational expressions with unlike denominators?

To add or subtract rational expressions with different denominators, you need to find a common denominator. Multiply each fraction by the necessary factors to achieve the common denominator. Then, distribute and simplify the expressions before combining them into a single fraction.

### Q: What is the first step in adding or subtracting rational expressions?

The first step is to identify the common denominator. This is done by finding the least common multiple (LCM) of the denominators. Once you have the common denominator, you can proceed with multiplying each fraction by the necessary factors.

### Q: Why is it important to simplify the expressions before combining them into a single fraction?

Simplifying the expressions helps to reduce the fraction to its simplest form. It also allows for easier combining of the numerators. By simplifying, you can avoid complications and errors in the final answer.

### Q: Can you cancel out common factors in rational expressions when adding or subtracting?

Yes, if there are common factors in the numerator and denominator of rational expressions, they can be canceled out. This can help simplify the expressions and reduce the final answer.

## Summary & Key Takeaways

• To add or subtract rational expressions, you need to find a common denominator.

• Multiply each fraction by the necessary factors to get the common denominator.

• Distribute and simplify the expressions before combining them into a single fraction.