Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo

Key Terms

boundary line
The line with equation Ax+By=CAx+By=C that separates the region where Ax+By>CAx+By>C from the region where Ax+By<CAx+By<C.
geoboard
A geoboard is a board with a grid of pegs on it.
graph of a linear equation
The graph of a linear equation Ax+By=CAx+By=C is a straight line. Every point on the line is a solution of the equation. Every solution of this equation is a point on this line.
horizontal line
A horizontal line is the graph of an equation of the form y=by=b. The line passes through the y-axis at (0,b)(0,b).
intercepts of a line
The points where a line crosses the x- axis and the y- axis are called the intercepts of the line.
linear equation
A linear equation is of the form Ax+By=CAx+By=C, where A and B are not both zero, is called a linear equation in two variables.
linear inequality
An inequality that can be written in one of the following forms:
Ax+By>CAx+ByCAx+By<CAx+ByCAx+By>CAx+ByCAx+By<CAx+ByC

where AandBAandB are not both zero.
negative slope
A negative slope of a line goes down as you read from left to right.
ordered pair
An ordered pair (x,y)(x,y) gives the coordinates of a point in a rectangular coordinate system.
origin
The point (0,0)(0,0) is called the origin. It is the point where the x-axis and y-axis intersect.
parallel lines
Lines in the same plane that do not intersect.
perpendicular lines
Lines in the same plane that form a right angle.
point–slope form
The point–slope form of an equation of a line with slope mm and containing the point (x1,y1)(x1,y1) is yy1=m(xx1)yy1=m(xx1).
positive slope
A positive slope of a line goes up as you read from left to right.
quadrant
The x-axis and the y-axis divide a plane into four regions, called quadrants.
rectangular coordinate system
A grid system is used in algebra to show a relationship between two variables; also called the xy-plane or the ‘coordinate plane’.
rise
The rise of a line is its vertical change.
run
The run of a line is its horizontal change.
slope formula
The slope of the line between two points (x1,y1)(x1,y1) and (x2,y2)(x2,y2) is m=y2y1x2x1m=y2y1x2x1.
slope of a line
The slope of a line is m=riserunm=riserun. The rise measures the vertical change and the run measures the horizontal change.
slope-intercept form of an equation of a line
The slope–intercept form of an equation of a line with slope mm and y-intercept, (0,b)(0,b) is, y=mx+by=mx+b.
solution of a linear inequality
An ordered pair (x,y)(x,y) is a solution to a linear inequality the inequality is true when we substitute the values of x and y.
vertical line
A vertical line is the graph of an equation of the form x=ax=a. The line passes through the x-axis at (a,0)(a,0).
x- intercept
The point (a,0)(a,0) where the line crosses the x- axis; the x- intercept occurs when yy is zero.
x-coordinate
The first number in an ordered pair (x,y)(x,y).
y-coordinate
The second number in an ordered pair (x,y)(x,y).
y-intercept
The point (0,b)(0,b) where the line crosses the y- axis; the y- intercept occurs when xx is zero.
Order a print copy

As an Amazon Associate we earn from qualifying purchases.

Citation/Attribution

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at https://openstax.org/books/elementary-algebra-2e/pages/1-introduction
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/elementary-algebra-2e/pages/1-introduction
Citation information

© Jan 23, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.