Functions which have straight line graphs are called linear functions (for the obvious reason). These functions can always be written in the form
Finding Points on a Line
To find points on the line y = mx + b,
Find two points on the line y = 2x + 1:
Point 1 - Choose x and solve for y:
Let x =1. Substitute x = 1 into y = 2x + 1 and solve for y.
y = 2(1) + 1 = 2 + 1 = 3
Hence (1,3) is one point on the line y = 2x + 1.
Point 2 - Choose y and solve for x:
Let y = -3. Substitute y = -3 into y = 2x + 1 and solve for x.
Hence (-2,-3) is another point on the line y =2x+1.
Follow the above example and try some of the following exercises: