What is the definition of "linear function"?

In calculus and related mathematical areas, a linear function is a polynomial function of degree zero or one or is the zero polynomial. In linear algebra and functional analysis, a linear function is a linear map.

The linear function form is y = f(x) = a + bx. A linear function has one independent variable and one dependent variable. The independent variable is x, and the dependent variable is y. The a is the constant term or the y intercept. It is the value of the dependent variable when x = 0. The b is the coefficient of the independent variable. The b is also known as the slope and gives the rate of change of the dependent variable.