The sentence
"Distance of 5 units from the number 7"
The part "From the number 7" indicates that you have to start counting from 7 on. Then the left bound of the interval is number 7.
To determine the right bound of the interval you have to count 5 units starting from 7, so add 5 to 7

The right bound of the interval is 12.
So, the values of x within the distance described by the sentence are: (7,12)