Download Pre-Algebra 8-2 Notes Completed

Linear Equations in Two Variables
(8-2)
You can model relationships using:

Equation

Table of Values

Graph
Y=x+4
x
2
1
0
-1
-2
y
6
5
4
3
2
Model each rule with a table of values and a graph
Step 1—Make a Table
Step 2—Choose values for the independent variable “x”
o It is good to pick small numbers that will easily fit on a graph
o It is good to pick positive numbers, negative numbers and 0
o The most common values for x are: 2, 1, 0, -1, -2
o If the function multiplies x by a fraction, it is best to use multiples of the
denominator so that the f(x) values are whole numbers
Step 3—Calculate each value for the dependent variable “y”using the equation
Step 4—Graph each ordered pair in the table and connect the points
1
Ex. y = x – 5
x
y=x–5
(x,y)
Ex. y = 2x – 3
x
y = 2x – 3
(x,y)
2
Ex. y = -x + 6
x
y = -x + 6
(x,y)
Ex. y = -2x – 4
x
y = -2x – 4
(x,y)
3