📖Definition
An algebraic expression is a mathematical phrase that contains numbers, variables (letters representing unknown values), and operations (+, -, ×, ÷). Unlike equations, expressions don't have an equals sign. Examples: 3x + 5, 2a² - 4b, 7y.
📐Formula
In 3x + 5: 3x and 5 are terms, 3 is the coefficient of x, x is the variable, and 5 is a constant. Terms are separated by + or - signs.
📝Step-by-Step Guide
Identify the Parts
Find the terms, coefficients, variables, and constants in the expression.
Combine Like Terms
Add or subtract terms that have the same variable raised to the same power.
Distribute When Needed
Multiply a term outside parentheses by each term inside.
Evaluate the Expression
Substitute given values for variables and calculate the result.
⚠️Common Mistakes to Avoid
- Combining unlike terms (3x + 2y ≠ 5xy)
- Forgetting to distribute to all terms in parentheses
- Confusing expressions with equations
- Incorrectly handling negative signs when distributing
- Adding exponents when combining like terms
✏️Practice Problems
Simplify 4x + 3x
Answer: 7x
Simplify 3(2x - 4) + 5x
Answer: 11x - 12
Evaluate 2x² - 3x + 5 when x = -2
Answer: 19
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