Consider this option:
1. if to re-write the condition, it is given: total time t=8 hours; upstream=downstream=6 miles; V_boat=4 m/h., V_current=V=?
2. note, that total time=time_upstream+time_downstream, where time_upstream=6miles/(V_boat-V) and time_downstream=6miles/(V_boat+V). Using this it is possible to make up and solve the following equation:

answer: √10
P.S. the roots of the equation are √10 and (-√10), only positive values is needed for V.
Answer:
With this form, we can tell that the x intercepts are x=6 and x=-2. So the x coordinate of the vertex is 2
Step-by-step explanation:
465+18 = 483
The fraction was just to throw you off, it's not too hard if you look carefully since you get a whole number from it