Here's the whole thing.
The formula for converting degrees Celsius, C, to degrees Fahrenheit, F, is F = (9/5)C + 32.
a Convert 30◦F to Celsius.
b Convert 30◦C to Fahrenheit.
c If x◦C = x◦F find x.
d If (x + 10)◦C = x◦F find x.
e If 2x◦C = x◦F find the value of x. f If k◦F = (−3k)◦C find k.