9514 1404 393
Answer:
1/4
Step-by-step explanation:
The common ratio is the ratio of successive terms:
16/64 = 4/16 = 1/4
The common ratio is 1/4.
D it can not be factored because it 7 can not be broken down into nothing else
Answer:
3
Step-by-step explanation:
Some function [] rounds DOWN a number to the nearest integer. For example [1.5]=1, [2]=2, [-1.5]=-2, ...
Thus [-1.6]+[3.4]+[2.7]=-2+3+2=3.
Notice that

, so

Then taking the positive square root gives

so
and
.
For sake of convenience, reverse the series, then it would be:
21,19,17.....7
a=21, d = -2,
s(4) = 4/2 (21+15)
s(4)=2(36)
s(4) = 72