The equation C = 5 9 F − 160 9 gives the relation between temperature readings in Celsius and Fahrenheit.

There is an issue with the question. The correct equation is as follows: the formula establishes the relationship between Celsius and Fahrenheit temperature readings. Knowing the Fahrenheit value ''F'' allows us to calculate Celsius ''C'', defining a function C(F) dependent on F. For part (a), we affirm that C is indeed a function of F. For part (b), we seek the mathematical domain of this function, which is all real numbers since there are no restrictions. Thus, the domain is Dom (C) = ( - ∞, + ∞). In part (c), water remains in liquid form at normal atmospheric pressure within the temperature range of 0 to 100 Celsius, so the range is Rang (C) = (0,100). We then determine the domain corresponding to this range by solving for variable ''F''; for C = 0 and C = 100 we find the relevant values for F. Consequently, the domain pertaining to liquid water temperature is Dom (C) = (32,212). Finally, for part (d), we simply substitute to find C where F = 71, which yields C ≈ 21.67 °C.