The line equation in slope-intercept form is ,

where m is the slope and b is the y-intercept.

Write the two functions as co-ordinates

as

as

First find the slope

m =

    =                   (Substitute and )

   =                   (Add: )

   =                          (Product of two same signs is positive)

     = 5                             (Divide: )­­

The line crosses the y-axis at (0, 4). So the y-intercept is 4.

Substitute and in slope-intercept form line equation.

                       (Simplify)

The function is .