Question

Please help with this sequence question

Answer 1

Answer:

1,048,576

Step-by-step explanation:

We can tell that this is a geometric sequence because each new term is a multiple of the previous term.  The common ratio is -2.

The pertinent formula is a(n) = -2 · (-2)^(n-1).

Thus, the 20th term of this sequence is a(20) = -2 · (-2)^(20-1), or

a(20) = -2 · (-2)^19, or 2^20, which comes out to 1,048,576 (same as the fourth possible answer).