The yield, YYY, of a certain chemical reaction is related to the operating temperature, xxx, by the equation
Y=5x+15(2x−8)2,x∈R,x≠4 Y = \frac{5x + 15}{(2x - 8)^2}, \quad x \in \mathbb{R}, \quad x \neq 4 Y=(2x−8)25x+15,x∈R,x=4where x x\,x is measured in degrees Celsius.
Use calculus to find the set of values of x x\,x for which the yield Y Y\,Y is increasing.