f(x)=5/9 (x- 32) f=77

Question

f(x)=5/9 (x- 32) Wanted to convert todays high of 77°F to °C

Answer 1

Yes, this is the conversion formula to Celsius where C=f(x).

1. Subtract 32 from 77=45. So this means 45 Fahrenheit degrees above freezing (measured at 32F).
2. Celsius degrees are 5 ninths of Fahrenheit degrees because the range of Fahrenheit is 32 to 212 for the freezing and boiling points of pure water=180 degrees Fahrenheit; while 0-100 is the range for Celsius. 100/180=5/9.
3. 5/9*45=25C. This is 25 Celsius degrees above freezing

Incidentally, -40C is the same as -40F. This is the only temperature where the numbers are the same.