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 )

    =                         (Subtract:)­­

    = 1.                           (Divide:)­­

The line crosses the y-axis at (0, 2). So the y-intercept is 2.

Substitute and in slope-intercept form line equation.

                (Simplify)              

The function is .