#### Vertical line test

A set of points on a rectangular coordinate system is the graph of $y$ as a function of $x$ if and only if no vertical line intersects the graph at more than one point.

#### Vertex

The point at which two or more border lines of a region intersect.

#### Verbal mathematical model

Words that describe how real-life values are related. Verbal models can be expressed using math symbols.

#### Variables

A collection of letters used in combination with constants using addition, subtraction, multiplication, or division to create an algebraic expression.

#### Variable factors

The variable part of a term. $ab$ in $6ab$.