Answer:
parallelogram
Step-by-step explanation:
 
        
                    
             
        
        
        
This should be easy because we just have to use substitution method. Substitute the value of x from the second equation into the x of the first equation. 
                         -4(2y) + 11y = 15
                         -8y + 11y = 15
                                   3y = 15   ; y = 5
Substitute this value of y to either the first or second equation.
                                        x = 2(5) = 10
The ordered pair is therefore (10,5).
        
             
        
        
        
Yes it is a geometric sequence and the common ratio is 2/3