Patrick B. answered 05/09/19
Math and computer tutor/teacher
C = (5/9)F - 17.778 = (5/9) (F - 32) <--- this is the EXACT FORMULA
(9/5)C = F - 32
(9/5)C + 32 = F
check: Let t be the temperature
F(C(t)) =
(5/9) [ (9/5)t + 32 -32] =
(5/9) [ (9/5)t ] = t
AND
C(F(t)) =
(9/5) [ (5/9)(t - 32)] + 32 =
(9/5)(5//9)(t-32) + 32 =
t - 32 + 32 = t