Answer:
131
Step-by-step explanation:
(-)86+45
86 + 45 = 131
-20a divided by 12b would be -1.6
The first term, a, is 2. The common ratio, r, is 4. Thus,
a_(n+1) = 2(4)^(n).
Check: What's the first term? Let n=1. Then we get 2(4)^1, or 8. Is that correct? No.
Try this instead:
a_(n) = a_0*4^(n-1). Is this correct? Seeking the first term (n=1), does this formula produce 2? 2*4^0 = 2*1 = 2. YES.
The desired explicit formula is a_(n) = a_0*4^(n-1), where n begins at 1.
