Final answer:
The compound inequality that represents the day's temperature, which ranged between 68 degrees as the low and 84 degrees as the high, is 68 ≤ T ≤ 84.
Step-by-step explanation:
To represent the day's temperature with a compound inequality, we state that the temperature T was at least 68 degrees and at most 84 degrees. This can be written as:
68 ≤ T ≤ 84
This means the temperature T is greater than or equal to 68 but less than or equal to 84. This compound inequality includes all the possible temperatures that could have been recorded that day between the lowest and highest.