The linear equation that converts Fahrenheit (F) to Celsius (C) is given by the relation, 
(i) if the temperature is 86°F, what is the temperature in Celsius ?
(ii) If the temperature is 35°C, what is the temperature in Fahrenheit ?
(iii) If the temperature is 0°C, what is the temperature in Fahrenheit and if the temperature is 0°F, what is the temperature in Celsius?
(iv) What is the numerical value of the temperature which is same in both the scale ?
(i) 
°C
(ii)
350×9 = 5f – 160
5f = 3150 + 160
f = 662°F
(iii) If the temperature is 0°C, then the temperature in Fahrenheit will be-
∵ 
5f = 160
f = 32°F
And if the temperature is 0°F, then the temperature in Celsius will be-
∵ 
C = – 17.778
(iv) Since, both are equal, let C = f
⇒ 
⇒ 9f = 5f – 160
⇒ 4f = – 160
⇒ f = – 40°F
∴ the numerical value of the temperature which is same in both the scale is – 40