To convert a temperature from Fahrenheit to Celsius, you can use the formula C =5(F −32),whereC is the temperature in degrees Celsius and F is the temperature in degrees Fahrenheit. How would I use formula to work out the Celsius equivalent of −10◦F.
Many thanks

You have the formula wrong
C = (5/9)(F-32)
check
when F = 32, C = 0 freezing point- right
when F = 212, C=100 boiling point - right
so
put in -10 for F
C = (5/9)(-42)
I think you can do that.