Line pases through point (6,2)
Its slope is -5/2
The fomula for a linear function is y=b+mx
b is the y-intercept
m is the slope.
Using the coordinate pair (6,2) and the value of the slope you can calculate the value of the y-intercept:

The y-intercept of the line is 17, so the linear function can be writen as:
