# Chapter Eight Linear Functions and Graphing

## 20 terms

### domain

the set of first coordinates of the ordered pairs of a relation.

### function

a relation where each number in the domain is paired with exactly one number in the range.

### function rule

an equation that describes a function.

### linear equation

an equation whose graph is a line.

### linear inequality

looks like a linear equation, but with an inequality symbol.

### negative correlation

one set of data values increase as the other set decreases.

### no correlation

there is no relationship between data sets.

### positive correlation

both sets of data values increase.

### range

the set of second coordinates of the ordered pairs of a relation.

### relation

a set of ordered pairs.

### scatter plot

a graph with points plotted to show a possible relationship between two sets of data.

### slope

a ratio that describes the tilt of a line.

### slope-intercept form

y=mx+b, where m is the slope and b is the y-intercept of the line.

### solution

is any value or values that make an equation or an inequality true.

### line of best fit

a line drawn in a scatter plot to fit most of the dots and shows the relationship between the two sets of data

### vertical-line test

is something that allows you to describe graphically whether a relation is a function.

### y-intercept

the y-coordinate of the point where the line crosses the y-axis.

### point-slope form

y-y1 = m(x-x1), where m is the slope and (x1,y1) is the point the line is passing through.

### standard form of a linear equation

Ax + By = C, where A,B, and C are real numbers, and A and B are not both zero.

### x-intercept

the x-coordinate of the point where a line crosses the x-axis.