Algebra I

Pre-Algebra Skills: Combining Like Terms

1. What is 4 apples plus 5 apples?

This is simple. All you have to do is add 4 and 5. What do you get? 9.

Be careful!! When writing your final answer, you must specify! You cannot just write 9. 9 what? 9 monkeys? 9 toilets? BE SPECIFIC!!!

So, our final answer is 9 apples.

2. What is 4 apples plus 5 bananas?

This is a trick question, guys. You cannot combine these because they are NOT like terms. In the first problem, we were able to add them because they were BOTH apples-meaning that they are like terms. However, in this problem, you cannot combine the apples with the bananas.

So our answer will remain, 4 apples and 5 bananas.

Combine:

3. 4x+5x

This is a great example problem for what I mentioned in the previous lesson. x is a variable. In this problem, it does not mean multiply. HOWEVER when a variable is next to another number or variable it does mean to multiply. In this case, for example, it means 4 times (*) x. It would not make a difference if the variable were to be a different letter such as a or m.

In this problem, we are adding 5x with 4x. Our answer is 9x. You basically just add the terms (4 and 5) and leave the x's the same.

Try this on your own:

4. 4y+5x

What did you get? The correct answer is 4y+5x because they are not like terms, so you cannot combine them.

Now solve these:

5. 2+7x

6. 2x+7x

Answers:

5. 7x+2 OR 2+7x (the correct way to format an answer is ax^2+bx+c)

6. 9x

Let's try these:

7. 3a+4b-7a+5b

In this problem, we can combine 3a and -7a to get -4a. We can combine 4b and +5b to get 9b.

Our final answer turns out to be -4a+9b.

Solve:

8. 2x+7-6y+5x-4+2y

9. How do you know which terms to combine and which terms not to combine?

Answers:

8. 7x-4y+3

9. If the terms are like, [if they both have the same variable (x)] and not when they have different variable or if one term has a variable and one doesn't.

That's all for this lesson! If you have any questions, comments, or concerns, please comment below and/or message me privately!