How to combine like terms with negative numbers in pre-algebra - High School Math

To combine like terms, combine the numbers as you would a normal addition or subtraction problem:

Therefore, = 8x - 8y.

Adding and subtracting negative integers is confusing if you don't use parentheses right. As long as you remember to keep them in the right places and stay neat, it is easy. Subtracting negative numbers is the same as adding a positive number, and adding a negative number is the same as subtracting a positive number. So, we could rewrite the equation like this:

To simplify a problem like the example above we must combine the like termed variables.

Like terms are the numbers that have the same variable, in this example, and .

Separate the s to get

Then perform the necessary addition to get

Then separate the ’s to get

Then perform the necessary subtraction to get

We then combine our answers to have the simplified version of the equation .

Let's start with our equation, .

Subtract from both sides:

Combine our s:

Divide both sides by :

However, the problem is asking for not , so multiply both sides by :

X is the only term that appears twice in the equation. Since both are positive numbers, we can add the X terms to simplify the equation.

Remember, adding a negative number is the same as subtracting a positive number. That means we can think of this problem as .

If we think of this on a number line, we start at , move left three units because of the , then move left again by one more unit for the , giving us a total of .

Here, we are interested in combining like terms. Like terms are those with the same variable,.

When combining terms with in them, we add the coefficients. Thus, we have , and .

Therefore, we have .