12. Find the slope of the secant line through the points (a, f(a)) and (a t h, f(a + h)).13. Explain how this will help you to find the slope of the line tangent to f(x) at the point (a, f(a)). 14. Using your answers from # 12 and # 13, find the slope of the line tangent to f(x) at the point (a, f(a)). 15. Use your answer to # 14 to find the slope of the line tangent to f(x) at the given point. Draw a sketch in each case (graph paper attached). (i) The line tangent to f(x) at the point (1, f(1)) has slope (ii) The line tangent to f(x) at the point (0, f(0)) has slope (iii) The line tangent to f(x) at the point (-1, f(-1)) has slope