I reccomend the search bar up at the top ("What is your question") before you ask questions, to make sure they're not already answered.
There is a formula d = rt, distance = rate*time. So
r = d/t.
r = 7mi/55min = 0.127mi/min
Or another way to see this:
2x + 9 < 0
2x < -9
x < -4.5
x> -12
x = {-11, -10, -9, -8, -7, -6, -5}
3.5 seconds!
hope this helps you out, and i’m sorry if i’m wrong!