Question

Charlie uses the function f(x) = 2x2 + 5x + 3 to track the temperature of a substance, where x represents the time. When you evaluate f(5) you find that the temperature of the substance is 78°C. What is the domain of the situation of Charlie's quadratic function?
A)
all real numbers


B)
all real numbers less than zero


C)
all real numbers greater than 1


D)
all real numbers greater than zero

Answer 1

THE ANSWER IS D.
The domain of the Charlie's function is all real numbers greater than zero. The function alone would have a domain of all real numbers. In the situation given, time cannot be negative, and therefore, cannot be a part of the domain.