A variable is concept introduced in algebra to represent unknown values with symbols. This allows mathematicians to solve for unknown quantities, manipulate math expressions using the laws of math, and to express formulas using variables as placeholders. For example, the latin letter is often used as a variable like in the expression below.

In plain language, this is a statement that the number is equal to the result of multiplied by the variable plus . Using the properties of equality, the statement can be manipulated to solve for the value of . This is shown in the steps below.

Start with the statement of equality.

Subtract the value from both sides.

Simplify the left-hand and right-hand sides of the equation.

Divide both sides by .

Simplify the fractions.

The value makes this statement true.