Adding And Subtracting Polynomials


Related Pages
Algebra Terms
Algebraic Expressions
Adding & Subtracting Functions
More Algebra Lessons
Grade 7 Math Lessons

In these lessons, we will look at how to add and subtract polynomials.




Share this page to Google Classroom

The following diagram shows examples of adding and subtracting polynomials. Scroll down the page for more examples and solutions on how to add and subtract polynomials.

Add Polynomials

Adding Polynomials

Adding polynomials involves combining like terms.

Example:
Add the polynomials 5x – 2 + y and –3y + 5x + 2

Solution:
5x – 2 + y + (–3y + 5x + 2)
= 5x + 5x + y – 3y – 2 + 2
= 10x – 2y

Example:
Find the sum of –7x3y + 4x2y2 – 2 and 4x3y + 1 – 8x2y2

Solution:
–7x3y + 4x2y2– 2 + 4x3y + 1 – 8x2y2
= –7x3y + 4x3y + 4x2y2– 8x2y2 – 2 + 1
= –3x3y – 4x2y2 – 1




Subtracting Polynomials

To subtract polynomials, remember to distribute the – sign into all the terms in the parenthesis.

Example:
Simplify –4x + 7 – (5x – 3)

Solution:
–4x + 7 – (5x – 3)
= –4x + 7 – 5x + 3
= –9x + 10

Example:
Simplify (5x2 + 2) – (– 4x2 + 7) + (– 3x2 – 5)

Solution:
(5x2 + 2) – (– 4x2 + 7) + (– 3x2– 5)
= 5x2 + 2 + 4x2– 7 – 3x2– 5
= 5x2 + 4x2– 3x2 + 2 – 7 – 5
= 6x2 – 10

How To Add And Subtract Polynomials?

To add polynomials

  1. Combine like terms.
  2. Write in descending order.

Examples:

  1. (4x2 + 8x - 7) + (2x2 - 5x - 12)
  2. (5 + 24y3 - 7y2) + (-6y3 + 7y2 + 5)
  3. (t2 - t + 5) + (7t2 - 4t - 20)

To subtract polynomials

  1. Rewrite the subtraction as addition.

To change subtraction to addition, we must add the opposite, or additive inverse. 2. Combine like terms. 3. Write in descending order.

Examples:

  1. (4x2 + 8x - 7) - (2x2 - 5x - 12)
  2. (6x4 + 3x3 - 1) - (4x3 - 5x + 9)
  3. (1.5y3 + 4.8y2 + 12) - (y3 - 1.7y2 + 2y)


Examples Of Adding And Subtracting Polynomials

Examples:

  1. (2x5 - 6x3 - 12x2 - 4) + (-11x5 + 8x + 2x2 + 6)
  2. (-9y3 - 6y2 - 11x + 2) - (-9y4 - 8y3 + 4x2 + 2x)

Adding And Subtracting Polynomials

Adding polynomials and subtracting polynomials is essentially combining like terms of polynomial expressions. When adding and subtracting polynomials, they can either be arranged vertically or grouped according to degree. A knowledge of polynomial vocabulary is important before adding and subtracting polynomials. Multiplying monomials and binomials is another type of operation with polynomials.

Examples:

  1. (4x2 - 3x + 2) + (5x2 + 2x - 7)
  2. (5x3 + 7x2 - x) + (8x3 + 4x - 5)
  3. (8x2 + 2x) - (10x2 + 2x - 9)
  4. -(6x3 - 4x) - (2x3 + x2 -2x)

Adding And Subtracting Polynomials

Examples:

  1. (x2 + 4x + 5) + (6x + 3)
  2. 2(x4 + 5x) - 6(x4 + 8x - 3)


Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.
Mathway Calculator Widget



We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.