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Lesson 4: Combining like terms

# Intro to combining like terms

In simple addition we learned to add all the numbers together to get a sum. In algebra, numbers are sometimes attached to variables and we need to make sure that the variables are alike before we add the numbers. Created by Sal Khan.

## Want to join the conversation?

• Yes, and you can also do this with other variables, as long as the variables are the same. (numerical value is just what you add or subtract)
• this might seem kind of strange but when i was trying to figure out how to add like terms i stumbled upon the fact that adding like terms can be solved by doing the distributive property in reverse. i am not sure if this makes sense or not, but it made sense to me.

for example:

2X + 3X = X(2+3)= X(5) = 5X

i do not like learning rules without understanding why the rules work. i know that you are suppose to simply add the coefficients of like terms and be done with the problem. but is that a shortcut/rule that was made instead of doing the distributive property in reverse ?
• That's precisely right. Most people take a more laid-back approach and think that two things plus three things has got to equal five things, but you're right on target that the distributive law is what's going on behind the scenes to make that simple statement work out.
• Is zero prime, composite or neither?
• Zero is neither. Zero, I've been taught is just zero. Zero is special. So, to answer your question, zero is neither.
• You had to pick Chuck Norris
hahahahahahahahahahahahahahahahahaha
its beautiful!
but still
heres my question,
Could you take the exponents and divide them by itself if one of them is x^2 and it ends up as x=?
• You can't find the value for anything by dividing it by itself. x^2 divided by x^2 equals 1. So, it still is x=?.
And yes, it's hilarious that he chose Chuck Norris as a variable.
• Chuck Norrises or Chuck Norri? https://potato.io/
• I've had to go back on this video over and over, I still don't understand. It may be the fact that I'm just stupid and too slow to catch up with everyone else.
But seriously, here's what I have to say; When you have a simple question, such as this: -n + (-3) + 3n + 5
• When you're combining like terms, you're not actually solving for anything
(It's not an equation if you don't have the equal sign)
Combining like terms just means you add together anything you can.

-n + (-3) +3n +5
In your example, you have two types of numbers. You have numbers that are a multiple of n and you have regular numbers.

The first thing I usually do is rearrange the numbers so that all the like terms or numbers that can be added together, are next to each other, like this:

-n + 3n + (-3) +5

Then you can rearrange it some more to make it clear how to combine the like terms

3n-n + 5-3

2n + 2

Does that help?
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• That's Dwayne "The Rock" Johnson doing his iconic eyebrow thing.
• It's hard to take it serious when he's using Chuck Norris as values here.
• What is a `Chuck Norris`