If f(1) = 160 and f(n + 1) = –2f(n), what is f(4)?

If f(1) =160 and f(n+1)=-2f(n), What is f(4)?

Answer:

f(4) = – 1280

Step-by-step explanation:

Using the recursive rule and f(1) = 60 , then

f(2) = – 2f(1) = – 2 × 160 = – 320

f(3) = – 2f(2) = – 2 × – 320 = 640

f(4) = – 2f(3) = – 2 × 640 = – 1280