Find an equation for the rational function graph shown to the right. The equation for the rational function is f(x) =. (Simplify your answer.) -81 Let a be directly proportional to m and n, and inversely proportional to y. If a = 4 when m =9, n = 4, and y=2, find a when m = 2, n = 3, and y = 7. a = (Type an integer or a simplified fraction.) C Pairs of markings, a set distance apart, are made on highways so that police can detect drivers exceeding the speed limit. Over a fixed distance, the speed R varies inversely with the time T. For one particular pair of markings, R is 63 mph when T is 6 seconds. Find the speed of a car that travels the given distance in 9 seconds. R= mph (Round to the nearest whole number.)