What you’ll learn
Given a linear expression in one variable with two to six terms and rational coefficients, add or subtract the coefficients of like terms and write an equivalent simplified expression.
Key idea
Their coefficients can be combined because the variable part is common: 3x + 2x = 5x. A constant is like another constant, but it is not like an x-term. Likewise, x and x² are different kinds of terms.
Read a subtraction sign as part of the term that follows it. In 3x + 5 + 2x − 7, the coefficients of x combine to 5 and the constants combine to −2. The simplified expression is 5x − 2. Combining terms changes the form, not the value.
Worked example
Combine like terms and write an equivalent simplified expression.
5x + 2x - 3
- 7x - 3
Answer: 7x - 3
Quick Check
Analyze the proposed student response. Choose Correct or Incorrect.
12x - 4x - 5 Student response: 8x - 5