For this case we have the following equation:
 H (t) = - 16t ^ 2 + 28t
 When the dolphin finishes a jump, then the height is equal to zero.
 We have then:
 -16t ^ 2 + 28t = 0
 We look for the roots of the polynomial:
 t1 = 0
 t2 = 1.75 s
 Therefore, the dolphin takes 1.75 seconds to make a jump.
 Answer:
 it will take for the dolphin to make one jump about:
 t = 1.75 s
        
             
        
        
        
You have to move the decimal
        
             
        
        
        
Answer:
2(7.5x+3.5)
Step-by-step explanation:
I can't remember what these equations are actually called, however in order to solve this you simply multiply 7.5 by 2, and then 3.5 by 2. 
 
        
             
        
        
        
Answer:
a=1
b=81
c=9
Step-by-step explanation: