Answer
Decreases to a minimum of $4.8$, then increases to $6.2$
Work Step by Step
We are given the function:
$$f(x)=\dfrac{6.5x^2-20.4x+234}{x^2+36}.\tag1$$
Graph the function $f$.
We notice that right after a person eats food containing sugar the pH level decreases to a minimum of $4.8$ in about $6$ minutes.
Then the level of pH starts to increase and after one hour it reaches the value of
$$f(60)=\dfrac{6.5(60^2)-20.4(60)+234}{60^2+36}\approx 6.2$$.
The increase continues over time and gets closer and closer to $6.5$.
