The function f(x)=6.5x2−20.4x+234x2+36 models the pH level, f(x), of the human mouth x minutes after a person eats food containing sugar. a) Sketch a graph of the function using the window size [0,70]by [3.5,7]b) After eating sugar, when is the pH level the lowest? What is the pH level at this time?c) What is the normal pH level of the human mouth?d) Find the horizontal asymptote and describe what it means of the mouth's pH level over time.