Alright, lets get started.
At the beginning of her training, she is able to run 2 miles without stopping means 2 will be in the addition when we will write the equation for her running miles.
Her goal is to increase her distance by three quarters of a mile each week.
Means in first week, she will add the distance = miles
Suppose she runs x weeks, so shee will add distance =
So, suppose she runs total number of miles = d, then
Where d is total numer of miles she runs
x is number of weeks : Answer
Hope it will help :)