(a) Find the slope of the tangent to the graph of f(x) at any point,
(b) Find the slope of the tangent at the given point,
(c) Write the equation of the line tangent to the graph of f(x) at the given point, and
(d) Graph both f(x) and its tangent line (use a graphing utility).
f(x) = x2 + x; (2, 6)