A coefficient is a numerical or constant quantity placed before and multiplying the variable in an algebraic expression. For example, in the algebraic expression , the number is the coefficient. It multiplies the variable , scaling its squared value.
A variable is a core concept in algebra where a symbol, usualy a lower case latin letter, is used as a placeholder in a math expression.
A constant is a value that does not change or vary in a mathematical expression or equation. It is the opposite of a variable, which can take on different values. Constants can be numbers, symbols, or even functions that remain unchanged throughout a given problem or context.