The sketch above shows graphs of the functions f and g. The graph of f is a parabola, with vertex B. The graph of g is a straight line which cuts the parabola at E on the y-axis and at A. The equation of f can be wnitten as y = az? - z - 6. The equation of g can be written as y =1+c The line SR is parallel to the y-axis, where R is a point on the graph of f and S 1s a point on the graph of g. 7.1 (a) Show that a = 2 (b) Find the co-ordnates of B (c) Find the co-ordinates of D 72 (a) Find the equation of the straight lne (b) Find the co-ordinates of A 73 Determine the maximum length of SR between E and A 7.4 Use the graphs (i e do not solve an inequality) to determine all values of z for which (S-9) (z) 20 75 Find the equation of the circle which has EA as a diameter D. 2