The function c(f) = (f – 32) converts a temperature, f, in degrees fahrenheit, to a
temperature, c, in degrees celsius. determine c(52), to the nearest degrees celsius.

That function is incorrect.
The correct function is . . . .    C(f) = (5/9) (f - 32) .

If a Fahrenheit thermometer reads 52° ,
then a Celsius thermometer should read . . .

         C (52) = (5/9) (52 - 32) =

                        (5/9) (20)  =  (11 and 1/9)°C.