The function is .

               (Apply derivative with respect to x)

            (The difference rule)

            (The power rule:)

We have to find the slope at point (3, )

So,                           (Substitute x = 3 and  y = )

To find the tangent line use point-slope form:

                        (Point-slope form)

                   (Substitute x = 3, m = and  y = )

Therefore the tangent line is .