Question

Enter a recursive rule for the geometric sequence. 10, −80,  640, −5120, ...

Answer 1

Answer:

an = 10 (-8)^(n-1)

Step-by-step explanation:

In a geometric series, each term is multiplied by a common ratio to get the next term.  Such that:

an = a₁ (r)^(n-1)

Here, the first term, a₁, is 10.  The common ratio, r, is -8, because each term is multiplied by -8 to get the next term.  So:

an = 10 (-8)^(n-1)

Your answer is correct, well done!

Answer 2

Answer:

a1 = 10

an = -8a (down) n - 1

I just took the test, these answers are correct! Good luck!