What is a variable expression?

A variable expression is a math phrase that includes:

• numbers

• variables (like x or y)

• operations (add, subtract, multiply, divide)

Important: Expressions do NOT have an equals sign.

Examples:

• 3x + 5

• 2y − 7

• 4(x + 1)

Parts of a variable expression

• Variable: a letter that represents a number (x, y)

• Coefficient: the number multiplying the variable

• Constant: a number without a variable

Example: 5x + 2
Coefficient = 5
Variable = x
Constant = 2

Evaluating a variable expression

To evaluate, substitute a number for the variable and simplify.

Example:
Expression: 3x + 4
If x = 2:

3(2) + 4 = 6 + 4 = 10