Module 4 Linear Graphs Summary

Summary Template – Module 4 Linear Graphs
Use this guide to help you create your own summary of the topics covered in Module 4.
1. Graphing an Equation:
a. To graph an equation, you need use the equation to generate pairs of coordinates
that can then be plotted on the Cartesian Plane.
b. Using the equation 𝑦 = 3𝑥 - 4 complete the table below so that you
have three pairs of coordinates that describe the equation.
𝒙 𝒚
0 -4
2 -2
2 2
Remember:
𝑥 and 𝑦 can take any values, so you
need to choose values for 𝑥 to
substitute into the equation to find 𝑦
(𝑥 = 0 is often a good place to start!)
c. Plot your coordinates on the grid below:
-4 -3 -2 -1 0 1 2 3 4 5 6
-15
-10
-5
0
5
10
15
x
y
Remember:
x Label the axes (𝑥 and 𝑦)

x Choose a suitable scale for each
axis based on the range of your 𝑥
and 𝑦 coordinates – you must go
up in even steps!
x Plot your coordinates (𝑥, 𝑦)
x Join your coordinates with a
straight line and extend in both directions
d. Why should you extend your straight line on the graph in both directions?
Extending the straight line on the graph allows for other points that lie within the line to be
observed. This is vita especially in using the line graph to model future predictions in areas such
sales growth in firms.
2. Finding an Equation from a Graph
a. For a linear equation in the general (slope-intercept) form:
𝑦 = 𝑚𝑥 + 𝑐
𝑥 and 𝑦 are independent and dependent variables respectively.
𝑚 is the slope of the equation
𝑐 is the y intercept, that is the value of y when x is zero (MathPlanet, 2019).
b. Using the Rise-over-Run Method:
i) Draw a suitable triangle onto the graph
and label the ‘rise’ and the ‘run’