The label on the cars antifreeze container claims to protect the car between -30c and 130c. to convert celsius temperature to fahrenheit, the formula is c=5/9(f-32).

C = 5/9(F - 32)

C = -30
-30 = 5/9(F - 32)
-30 = 5/9F - 160/9
-30 + 160/9 = 5/9F
-270/9 + 160/9 = 5/9F
-110/9 = 5/9F
-110/9 * 9/5 = F
- 990/45 = F
- 22 = F

C = 5/9(F - 32)
C = 130

130 = 5/9F  - 160/9
130 + 160/9 = 5/9F
1170/9 + 160/9 = 5/9F
1330/9 = 5/9F
1330/9 * 9/5 = F
11970/45 = F
266 = F

So in Fahrenheit temp, the the car is protected between -22 F and 266 F

The answer is part a: use