Suppose a sequence satisfies the given recurrence relation and initial conditions. Find an explicit formula for the sequence. 1. ak = 7ak-1-10ak-2, for every integer k 2 ao = -2, a = 2 2. bk=bk-1+6bk-2, for every integer k 2 bo = 0, b = 3 3. ak= 6ak-1-9ak-2, for every integer k 2 ao = 1, a = 3 4. bk 2bk-1-bk-2, for every integer k 2 == bo = 1, b = 4