6.5x2-52.5x+941 The function f(x)= models the pH level, f(x), of a mouth x minutes after +145 eating food containing sugar. The graph of this function is shown to the right. Complete parts (a) through (e). pH Level of the Mouth 5- 12 24 36 Number of Minutes after Eating 48 60 a. Use the graph to obtain a reasonable estimate, to the nearest tenth, of the pH level of the human mouth 42 minutes after a person eats food containing sugar. The pH level after 42 minutes is (Round to the nearest tenth as needed.)