Refer to the graph of y = f(x) = x" + x shown. a) Find the slope of the secant line joining (1, f(1)) and (4, f(4)). 6) Find the slope of the secant line joining (1, f(1)) and (1 + h, f(1 + h)). c) Find the slope of the graph at (1, f(1)). d) Find the equation of the tangent line to the graph at (1, f(1)). 5 -23