The equation for k is, 

Here slope is 8/7..
Since, line I is perpendicular to k, the slope of the line I is, -7/8.
The general line equation is, 

Here, m is the slope and b is the y intercept.
As the line passes through the points (2, -15/4), we have, 

Thus, the equations are, 

The point slope form is, 
