The sequence < un > is defined by the recurrence un+1 = 3un+1\5un+3 initial condition of u1 = 1: need to show un in terms of fibonacci / lucas numbers

Ihave been given the number of guns per 100, and the total firearm-related deaths per 100,000. i have to find the actual number of guns per country and actual number of gun-related deaths. if somebody could show me how to do 1 question, i can finish the rest, i am just confused. tia

For a typical middle-income family, what is the estimated cost of raising a child to the age of 18? $145,500 $245,340 $304,340 $455,500

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?