<u>Understanding:</u>
The sum of a geometric series is, 
, with a being the start point and r is the common ratio. We can also use the following formula to make life easier 
, a is your start point, r is the common ratio, and n is the number of terms, which in our case is S7.
<u>Solution:</u>
Our start point is 1, 
,
The common ratio is 5, 
,
And finally, the number of terms is 7, 
.
The answer is [A] 19531.
Answer:
Step-by-step explanation:
1/9
(1*4) / (9*4) = 4/36
(1*4) / (9*4) = 5/45
The first one is the ratio as it is stated in the problem.
The second one multiplies top and bottom by 4
The third one multiplies top and bottom of the top ratio by 5.
The answer to the math problem is 8y^12
Its 10+20= 30 and 10++20=30
