Final answer:
The change in temperature after 3 days is -21/18 degrees Fahrenheit.
Step-by-step explanation:
The temperature is changing every day by -7/18 degrees Fahrenheit. To find the change in temperature after 3 days, we need to multiply the rate of change (-7/18) by the number of days (3). Multiply the numerators: -7 * 3 = -21. Multiply the denominators: 18 * 1 = 18. Therefore, the change in temperature after 3 days is -21/18 degrees Fahrenheit.