"Increasing" and "decreasing" are references to what the y-values do when the x-values increase.  
Attached is a copy of all four tables, marked with whether the y-values increased or decreased on each step (and it also shows how much that increase or decrease was.
The only table that does this is the top right table in the attachment, which is your second table.
 
        
             
        
        
        
Answer:
V=a^3
V=8 1/2^3
V=614.125
Step-by-step explanation:
 
        
                    
             
        
        
        
OK so here it goes:
1a. 10³
1b. 10²
1c. 10(tiny 6)
1d. 10³
1e. 10(tiny6)
1f. 10(tiny 5)
2a. 400
2b. 640,000
2c. 5,400
2d. 5,301,000
2e. is it multipcation or addition
2f. 607,200
2g. 0.948
2h. 0.0094
3a) 0.02, 0.2, 2, 20, 200, 2000
3b) 3,400,000 ; 34,000; 340, 3.4, 0.034
3c) 85,700; 8,570; 857, 85.7, 8.57, 0.857
3d) 444, 4440, 44,400; 440,000; 4,400,000; 44,000,000
3e) 0.95, 9.5, 950, 95,000; 950,000; 9,500,000
Hope this helps.
        
             
        
        
        
X-doubling periods
Y-height of bamboo
Y=ab^x
1) make a table of values
X Y
1 5
2 10
3 20
2) write equations and substitute
 5=ab^1 —> a=5/b^1 —> a=5/b
10=ab^2
Substitute into second equation 
10=(5/b)*b^2
10=5b^2/b
10=5b
b=2
Substitute back in
b=2
10=a*2^2
10=4a
a=5/2
End equation: 
Y=5/2*2^x
        
             
        
        
        
5/6 × 6 = 5 so 5/6 times 12= 10