3×y

3×y denotes the product of the constant 3 and the variable y. In algebra it is a linear term or monomial and is commonly written as 3y. The multiplication sign is often omitted, yielding 3y, or written as 3·y; by the commutative property, 3×y = y×3.

When treated as a function of y, f(y) = 3y is a linear function with slope 3 and y-intercept 0. The value of the expression depends on y: for example, if y = 5, 3×y = 15; if y = −2, 3×y = −6. The usual domain and range are all real numbers, though a restricted domain for y yields a restricted range for the product.

In graph form, the equation y = 3x (or f(y) = 3y) represents a straight line through the origin with slope 3 in the Cartesian plane. The expression is homogeneous of degree 1 and has coefficient 3, which scales y by a factor of 3.

Algebraically, 3y can be factored from expressions such as 3y + 6 = 3(y + 2). If y is a vector or matrix, 3y denotes scalar multiplication of that object (multiplying each component by 3).

Common uses include solving linear equations and inequalities, modeling quantities with direct proportionality, and serving as a basic building block in polynomials and algebraic expressions. In programming languages, the equivalent is typically 3*y. Related concepts include coefficients, monomials, and linear functions.