Arithmetic sequences have a common difference between consecutive terms.
Geometric sequences have a common ratio between consecutive terms.
Let's compute the differences and ratios between consecutive terms:
Differences:

Ratios:

So, as you can see, the differences between consecutive terms are constant, whereas ratios vary.
So, this is an arithmetic sequence.
 
        
             
        
        
        
I think it’s -1 because with rise/run it goes down 2 and over 2 but the line is going down, so it’s negative.
        
                    
             
        
        
        
P = 2(L + W)
L = W + 5
A = 4P + 2
P = 2(W + 5 + W)
P = 2(2W + 5)
P = 4W + 10
A = 4P + 2
A = 4(4W + 10) + 2
A = 16W + 42
A = L * W
A = W(W + 5)
A = W^2 + 5W
W^2 + 5W = 16W + 42
W^2 + 5W - 16W - 42 = 0
W^2 - 11W - 42 = 0
(W + 3)(W - 14) = 0
W - 14 = 0
W = 14 <==
L = W + 5
L = 14 + 5
L = 19 <==
P = 2(19 + 14)
P = 2(33)
P = 66
A = L * W
A = 19 * 14
A = 266
answer : length = 19, width = 14....perimeter = 66....area = 266
        
             
        
        
        
9 on the top as well so 9 x 2 18 3x2 6 3