Answer:
9x^2 - 49y^2
Step-by-step explanation:
 
        
                    
             
        
        
        
The given sequence is
a₁, a₂, ..., 

Because the given sequence is an arithmetic progression (AP), the equation satisfied is

where
d =  the common difference.
The common difference may be determined as
d = a₂ - a₁
The common difference is the difference between successive terms, therefore
d = a₃ - a₂ = a₄ - a₃, and so on..
The sum of the first n terms is

Example:
For the arithmetic sequence
1,3,5, ..., 
the common difference is d= 3 - 1 = 2.
The n-th term is

For example, the 10-term is
a₁₀ = 1 + (10-1)*2 = 19
Th sum of th first 10 terms is
S₁₀ = (10/2)*(1 + 19) = 100
 
        
        
        
Answer:
Equation 1
In the story it said Eli's mom doubled the money he left, that is what the two represents. 10 is the original amount he had. -k is the money he lost.
Equation 2
20 is the the result of the original 10 being multiplied. -2k, now the 2 is still the amount that the mom doubled his amount by, and the k is how much money Eli lost.
Hope this helps!!
 
        
                    
             
        
        
        
1 foot = 12 inch so 6 feet = 6*12 inch
6 feet = 72 inch
The height of the person in inch is = 72+1 = 73 inch
1 meter.............39.37 in
x meters.......... 73 in
x = 73/39.37 = 1.85 meters
        
             
        
        
        
ok so I am no expert (Actually i am it says it on my profile) but the answer is 69/5555*^ I hope that this helps you and if it was so easy then why can't ya do it buddy! lol jkjkjkjk