3.2 Drawing Linear Graph

 What is a Linear Graph?

Linear the word itself means straight. This is a line drawn in a graph that has no curves. To draw the linear graph we have to plot coordinates. 

Usually, an equation is given in the line equation format:

The equation will always have 2 variables x and y. The linear equation will always have a positive x or a negative x. 

• When y=x ( positive) 

• When y=-x (negative)

Some Special Cases 

• When:
•  y= 4 (Blue Line) 
•  y= 1 (Green Line) 
•  y= -2 ( Red Line) 

• When:
•  x= 4 (Blue Line) 
•  x= 1 (Green Line) 
•  x= -2 ( Red Line) 

 

How to Draw a Linear Graph?

The question would have an equation with 2 unknown variables x and y.

Examples: 

a) 2x-y=4

b) y-x=9

c) x= 3y-6

d) y= -7x-3

Step 1: Check if the question gives a range such as -4 ≤ x ≤ 4. This indicates x-axis should be from -4 to 4. Draw the x-axis and y-axis on graph paper accordingly.

Step 2: Draw a table of values. This table can be drawn in vertical and horizontal format. It should have at least 3 values for x. The values for x should be based on the range or x-axis drawn on the graph. 

Step 3: If the equation is not given in terms of y ( y=......). Rearrange to make the subject y or it's fine to continue with just substituting for the value of x to find the y coordinate.  

Step 4: Plot the coordinates accurately. Draw the line and label the line with the given equation

Extra Exercises to attempt.