Answer:
C; B
Step-by-step explanation:
The direct/explicit formula for a geometric sequence is the following:
Where <em>aₙ </em>represents the term <em>n</em>, <em>a</em> represents the initial value, and <em>r</em> represents the common ratio.
Therefore, to find the <em>nth</em> term, we just need to find the initial value and the common ratio.
1)
-8, 24, -72, 216...
The common ratio is the ratio between each consecutive term. Do two to confirm that they are indeed the same. Thus:
So, the common ratio is -3. And the initial value is -8. Thus, putting them into our equation:
Thus, the eighth term will be:
C
2)
Again, find the common ratio.
2, -14, 98, -686...
The common ratio is -7. The initial value is 2. Thus:
And the sixth term will be:
B