The equation given is \( T(x) = 2x + 10 \), where \( T(x) \) represents the temperature in degrees Celsius and \( x \) is the number of hours after noon.
To find the initial value, we evaluate the function at \( x = 0 \) (which corresponds to noon):
\[ T(0) = 2(0) + 10 = 10 \]
Thus, the initial temperature at noon is 10°C.
So the correct response is:
10°C