### linear equation in two variables

equation in two variables whose graph is a line

### parallel lines

lines in the same plane that do not intersect

### perpendicular lines

lines that intersect at a 90° angle

### point-slope form of a line

linear equation, where $m$ is the slope and $(x_1, y_1)$ is a point on the line, expressed as:

$y-y_1=m(x-x_1)$

### rise

vertical change between two points on a line

### run

horizontal change between two points on a line

### slope

ratio of the change in $y$ to the change in $x$ for two points on a line, represented as:

$\frac{\text{Rise}}{\text{Run}}$

### slope-intercept form of a line

linear equation, where $m$ is the slope and $b$ is the $y$-intercept of the line, expressed as:

$y=mx+b$

### standard form of a line

linear equation, where $A$, $B$, and $C$ are integers, $A$ is nonnegative, and $A$ and $B$ are both not zero, expressed as:

$Ax+By=C$

*x*-intercept

value of $x$ where a graph touches or crosses the $x$-axis

*y*-intercept

value of $y$ where a graph touches or crosses the $y$-axis