Question

What is the 20th term in the linear sequence 15, 7, -1, -9, -17

Answer 1

Hello from MrBillDoesMath!

Answer:

-137

Discussion:

It appears the 8 is subtracted from each term in the sequcnes as we proceed from left to right. The equation describing the nth terms is therefore:

a(n) = 15 - 8 * (n-1)

          a(1) = 15 - 8(0) = 15

          a(2) = 15 - 8*(2-1)   = 15 - 8 = 7

          a(3) = 15 - 8(3-1)  = 15 - 8(2) = 15 - 16  = -1

          etc

The 20th term is given by

a(20) = 15 - 8(20-1)

         = 15 - 8 * 19

         = 15 - 152

         = -137

Thank you,

MrB

Answer 2

Then answer is -137 I agreee