Question

He formula c = 5 9 (f − 32), where f ≥ −459.67, expresses the celsius temperature c as a function of the fahrenheit temperature f. find a formula for the inverse function. f= 9 5​c+32 what is the domain of the inverse function? (enter your answer using interval notation.)

Answer 1

should it not be 5/9?
Multiply both sides by 9/5
(9/5) * C = F - 32
Add 32
(9/5)*C + 32 = F

A very quick way to get an estimate is to use this formula which can almost be done in your head.
C = 40
2*C + 30 = F
2*40 + 30 = F
80 + 30 = F
110 = F