## Geometry and Trigonometry## Analytic Geometry |

## How are graphs used to solve equations? |

Any figure represented by an equation in two variables is a curve in two dimensions. For example, the equation 3*x* + 4*y* = 8 is also called a *linear function* because the solution represents a line (which is considered a “curve” in geometry) on a graph. There are also graphs of equations in three variables, with the solution as a surface—or the two-dimensional “outer layer” of a three-dimensional object.