Skill: Identify variables

A variable is a letter or symbol that stands for an unknown or changing number. A constant is a number that stays fixed. When a number is multiplied by a variable, it is called the variable’s coefficient.

Example

Identify the variable, coefficient, and constants in

$$3x+5=20$$

1. Look for the letter or symbol.
   The letter is $x$, so $x$ is the variable. Its value is unknown.

2. Look at the number next to the variable.
   The $3$ is multiplied by $x$, so $3$ is the coefficient of $x$.

3. Identify the numbers that do not change.
   The numbers $5$ and $20$ are fixed, so $5$ and $20$ are constants.

Therefore:

• Variable: $x$
• Coefficient: $3$
• Constants: $5$ and $20$