please help i will give brainliest

Answer:
Part 1: 2.4 + x
Part 2: 4(2.4 + x) = 14.8
Step-by-step explanation:
2.4 + x is the total distance covered every day.
We know that after 4 days, Bijan has run 14.8 miles, so in total he has run 4(2.4 + x) miles, which is equal to 14.8.
Extra: Here's how to work out x!
4(2.4 + x) = 14.8
9.6 + 4x = 14.8
4x = 5.2
x = 1.3
Hope that helps!