(a) Graph f and the secant lines passing through P(3, 15) and Q(x, f(x)) for x-values of 4, 3.5, 2.5. Find the slope of each secant line. To sketch the graph of f(x) = 8x - x, first construct a table of values by evaluating the function f(x) for various values of x. Consider x = 4. To evaluate f(x) with x = 4, substitute 4 for x in f(x). f(x)=8x-x2 f(4) = 8(4) - (4) = 16 16 Step 2 Similarly, evaluate f(x) for the values below, and complete the table. X 4 3.5 3 2.5 2 1.5