Answer:
x is the number of months
Step-by-step explanation:
On the first run, hence after 0 months, Sean ran 0.5 miles or
After 1 moth, Sean increased 2 miles to his run, hence during the first and second month, Sean ran 2.5 miles or
After 2 moths, Sean increased 2 miles more to his run, hence during the second and third month, Sean ran 4.5 miles or
After 3 moths, Sean increased 2 miles more to his run, hence during the third and fourth month, Sean ran 6.5 miles or
Using the same rule, we see that after x-months Sean will run