Answer:

Step-by-step explanation:
We have a geometric  sequence with:
 ,
,  , and
, and 
Where 
Sn is the sum of the sequence
r is the common ratio
 is the first term in the sequence
 is the first term in the sequence
n is the number of terms in the sequence
The formula to calculate the sum of a finite geometric sequence is:

Then:

Now we solve for 


 
        
             
        
        
        
Answer:
Step-by-step explanation:
x-y=14 
x-1/3y=1/10 
-y=14-x
y=-14+x 
take out the factors 
x-10/30y=3/30
30x-10y=3 
substitute
30x-10(-14+x)=3 
30x+140-10x=3-140 
20x/20=-137/20 
x=-6.85 
y=-14+(-6.85)
y=-20.85 
 
        
             
        
        
        
Only 20%of earths water is useable
        
             
        
        
        
I agree with this person that will be a good use
        
             
        
        
        
<h3>
Answer:  shaded region has area 107 square feet</h3>
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Work Shown:
A = area of larger rectangle
A = length*width = 9*15 = 135 square feet
B = area of smaller rectangle
B = length*width = 7*4 = 28 square feet
C = area of shaded region
C = difference in areas of A and B
C = A - B = 135 - 28 = 107 square feet