Key Terms Chapter 04: Graphs
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- Boundary Line
- The line with equation Ax+By=C that separates the region where Ax+By>C from the region where Ax+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=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=b. The line passes through the y-axis at (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=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+By≥CAx+By<CAx+By≤C
where A and B 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) gives the coordinates of a point in a rectangular coordinate system.
- Origin
- The point (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 m and containing the point (x1,y1) is y−y1=m(x−x1).
- 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) and (x2,y2) is m=y2−y1x2−x1.
- Slope of a Line
- The slope of a line is m=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 m and y-intercept, /((0,b)\) is, y=mx+b.
- Solution of a Linear Inequality
- An ordered pair (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=a. The line passes through the x-axis at (a,0).
- X-intercept
- The point (a,0) where the line crosses the x-axis; the x-intercept occurs when y is zero.
- X-coordinate
- The first number in an ordered pair (x,y).
- Y-coordinate
- The second number in an ordered pair (x,y).
- Y-intercept
- The point (0,b) where the line crosses the y-axis; the y-intercept occurs when x is zero.