Question

Given the following sequence, find the 15th term: 3,1,-1,-3,-5

Answer 1

-25 just subtract 2 everytime 

Answer 2

3, 1 ,-1, -3, -5
 -2  -2  -2   -2

a(n) = a₁ + d(n - 1)
a(n) = 3 - 2(n - 1)
a(n) = 3 - 2(n) + 2(1)
a(n) = 3 - 2n + 2
a(n) = -2n + 3 + 2
a(n) = -2n + 5

a(n) = -2n + 5
   a₁₅ = -2(15) + 5
   a₁₅ = -30 + 5
   a₁₅ = -25