Even without knowing what a variable is, we can sometimes make expressions with variables look simpler. This is done by simplifying our expression.

Here are vocabulary words that will help you understand the lesson better:

**Coefficient**: The number being multiplied to a variable (in \(2n\), \(2\) is the coefficient)**Reduce**: Combine or simplify by doing whatever operations we can**Term**: A part of an expression separated from the rest by addition (in \(3a + 6b\), \(3a\) is one term and \(6b\) is another term)**Like Terms**: Any terms in an expression where the variables are the same (\(3a\) and \(4a\), \(2b^2\) and \(5b^2\), note that \(2b^2\) and \(3b\) are not like terms)

Video Source (09:10 mins) | Transcript

Remember to follow the order of operations. Sometimes this means to use the distributive property to solve what’s in the parentheses.

When we see two different letters, we can easily know that we don’t have like terms, but can we add \(3a + 4a^2= ?\) Let’s say \(a = 3\), then \(a^2 = 9\). Because these are different numbers, the answer is no, we cannot add \(3a + 4a^2\). Any time we have different letters as our variables, or the same letter with different powers, we do not have like terms.

## Additional Resources

- Khan Academy: Intro to Combining Like Terms (04:32 mins, Transcript)
- Khan Academy: Simplifying Expressions (04:06 mins, Transcript)
- Khan Academy: Combining Like Terms - Challenge Problem (04:38 mins, Transcript)

### Practice Problems

**Simplify the following expressions:**

- \(7w − 2w\) (Solution
- \(5s − 7 − 3s + 11\) (Solution
- \(5a − 2b − 6 + 3a + 6b\) (Video Solution
- \(2v^{2}+6+3v-3v^{2}\) (Solution
- \(2 \lgroup 3-2t \rgroup + 5 \lgroup t + 3 \rgroup\) (Solution
- \(\lgroup 4 x + 3 y - 2z \rgroup - 2 \lgroup x + 3 z \rgroup\) (Video Solution

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