Use the figure below, which gives a graph of the function , to give values for the indicated limits. If a limit does not exist, enter none.
graph of a piecewise defined function, which is a downward opening quadratic function, with vertex at (0,7), for x in [-3,1].  the function is a line with slope 2 for x greater than 1, starting with an open circle at (1, -8).  there is a hole in the line at x=4, and a point plotted at (4, -4).
(a) = help (limits)
(b) =
(c) =
(d) =