Answer
F=-108.4
Work Step by Step
The formula for temperature is as follows: (F - 32) * 5/9
C=degrees Celsius
F=degrees Fahrenheit
Step 1) Given the temperature in degrees Celsius (-78), the exercise is asking for this same temperature in Fahrenheit. To do this, all you would have to do is substitute -78 for wherever you see C, and then solve for F (See Image)
Step 2) F will equal -108.4 after solving it