Find the sum of the first 9 terms of the geometric series:
3 + 21 + 147 + …

  20,176,803

Step-by-step explanation:

This geometric series has a first term of 3 and a common ratio of 21/3 = 7. The formula for the sum of n terms of a series with first term a1 and common ratio r is ...

 Sn = a1·(r^n -1)/(r -1)

For a1=3, n=9, and r=7, the sum is ...

  S9 = 3·(7^9 -1)/(7 -1) = 3·40353606/6 = 20,176,803

The sum of the first 9 terms is 20,176,803.

The first 9 terms are ...

  3 +21 +147 +1029 +7203 +

  50,421 +352,947 +2,470,629 +17,294,403

logv3(x+2)=1

rewrite in exponential form:

logb(x) = y is equal to b^y =x

b = 3, y = 1

now solve for x:

3^1 = x+2)

x = 3-2

x = 1

see the picture for the graph.