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## Algebra basics

### Course: Algebra basics > Unit 7

Lesson 1: Adding & subtracting polynomials# Adding and subtracting polynomials review

CCSS.Math: ,

Adding and subtracting polynomials is all about combining like terms. In this article, we review some examples and give you a chance for you to practice the skill yourself.

Adding and subtracting polynomials is an exercise in combining like terms. Let's walk through some examples.

### Example 1

**Simplify.**

Rewrite without parentheses:

Group like terms:

Simplify:

*Want to see another example? Check out this video.*

### Example 2

**Simplify.**

Rewrite without parentheses (being careful to distribute the negative):

Group like terms:

Simplify:

*Want to see another example? Check out this video.*

### Example 3

**Express E, plus, F as a trinomial.**

Rewrite without parentheses and color code like terms:

Group like terms:

Simplify:

*Want to see another example? Check out this video.*

## Practice

*Want more practice? Check out these exercises:*

## Want to join the conversation?

- What are polynomials used for?(49 votes)
- " Since polynomials are used to describe curves of various types, people use them in the real world to graph curves. For example, roller coaster designers may use polynomials to describe the curves in their rides. Combinations of polynomial functions are sometimes used in economics to do cost analyses, for example."

Also, you might find this interesting "Engineering Careers. Aerospace engineers, chemical engineers, civil engineers, electrical engineers, environmental engineers, mechanical engineers and industrial engineers all need strong math skills. Their jobs require them to make calculations using polynomial expressions and operations."(119 votes)

- I always forget to put the negative sign in front of the number if there is one and i get it wrong cause of that(37 votes)
- why is it important to learn polynomials?(16 votes)
- It is actually used in a lot of careers in the future, like engineering, finance, or other math-related fields.(7 votes)

- What method can I use to remember to put in my negative n positive sign ,

I’m having a little trouble with negative n positive.(5 votes)- - * - = +

- * + = -

+ * + = +

That's for multiplication rules. - * + is equal to + * -

As for addition and subtraction, whichever sign's number is larger, they will take that sign.

Example: -2 - (- 2) = -2 + 2 = 0

I hope this helped!(14 votes)

- How wouldn't it be -10y with the exponent of 2 if all the other numbers cncel out(6 votes)
- It's actually -10y^2 as -7y^2+-3y^2 = -7y^2-3y^2= y^2(-7-3)= -10y^2(5 votes)

- why does some of the exercises keep telling me to start over, when i have done it up to two to three times?(7 votes)
- I think he's right, but, don't push start over, unless you want to start over. lol(1 vote)

- do you guys have an easier method for this lesson?(5 votes)
- You may be over thinking this.

Adding polynomials is the same as combining like terms. If you can combine like terms, then you can add polynomials.

To subtract polynomials, you just need to remember to distribute the "minus" sign to all the terms in the polynomial being subtracted. Once you've done the distribution, you are back to combining like terms.

Hope this helps.(9 votes)

- Sometimes in subtracting polynomials I just dont know when to put like a - or a +(4 votes)
- I know! its hard to remember! sometimes i get confused between which negatives and positives to put and i mix up the signs! ive got an answer at this link explaining how to not get confused! :)

https://www.khanacademy.org/video/solving-equations-with-the-distributive-property?qa_expand_key=ag5zfmtoYW4tYWNhZGVteXJACxIIVXNlckRhdGEiHWthaWRfODY4NDgzODk3NjM3NzY3MzkyNzk3MjMxDAsSCEZlZWRiYWNrGICAuZTJyoUKDA

copy the whole link and it will take you there! hope this helped! :D(10 votes)

- for (3x+1)-(2x+3)

we do 3x+1-2x-3 like -1(2x+3)

is there video on khan academy explaining what's the fundamental behind this.(5 votes)- with -(2x+3), you can distribute the "-" itself: -(2x) -(+3) which basically says change all terms to their opposite sign, and creates -2x-3

Or, you can treat the "-" as -1. Remember "-x" is the same as "-1x". So, by changing the "-" to "-1", you are essentially doing the same thing.

-1(2x+3) = -1(2x) -1(+3) = -2x-3

You get the same result using either approach.

Hope this helps.(7 votes)