I think this is what it's asking for...
a) 17 is the total amount ran
5 is the number of miles
x is the hours (which is unknown)
you have to find x. the problem says that there are 5 miles per hour so your x would go with your 5. the 17 stays on the opposite side of the =
17=5x
b) to find the amount of time (x) just solve for x
17=5x is your equation
you now have to isolate the x (do this by dividing 5 on both sides of the equation)
5/x= x alone
17/5=3.4
3.4=x
* remember that x is hours in this problem, so round if you need too