"Like Terms"

It may help you to read Introduction to Algebra first

Like Terms

"Like terms" are terms whose variables (and their exponents such as the 2 in x2) are the same.


Note: the coefficients (the numbers you multiply by, such as "5" in 5x) can be different.


7x x -2x

Are all like terms because the variables are all x


(1/3)xy2 -2xy2 6xy2

Are all like terms because the variables are all xy2

Unlike Terms

If they are not like terms, they are called "Unlike Terms":

Unlike Terms Why they are "Unlike Terms"
  -3xy -3y 12y2 these are all unlike terms
(xy, y and y2 are all different)

Combining Like Terms

You can add like terms together to make one term:

Example: 7x + x

They are both like terms, so you can just add them:

7x + x = 8x

By the way ... why don't we write "1x" ?

It is just easier to write x. Imagine you were adding eggs:

7 eggs plus 1 egg is 8 eggs could be written 7 eggs + egg = 8 eggs


Example: 3x2 - 7 + 4x3 - x2 + 2

Some of the terms are like terms.

Combine like terms:

(3x2 - x2) + (4x3) + (2 - 7)

Then add like terms:

2x2 + 4x3 - 5