Answer: In mathematics, a variable is a symbol which functions as a placeholder for varying expression or quantities, and is often used to represent an arbitrary element of a set. In addition to numbers, variables are commonly used to represent vectors, matrices and functions
Step-by-step explanation:A symbol for a value we don't know yet. It is usually a letter like x or y.
Example: in x + 2 = 6, x is the variable.
Why "variable" when it may have just one value? In the case of x + 2 = 6 we can solve it to find that x = 4. But in something like y = x + 2 (a linear equation) x can have many values. In general it is much easier to always call it a variable even though in some cases it is a single value.
