Answer:
Width=4, and Length=17
Step-by-step explanation:
first you will make a variable for the width which i will say is x
now make it an equation (3x+5) (x) = 68
then solve 3x^2+5x=68
then 3x^2+5x-68=0
then x=4
then you have to substitute so 3(4)+5= 17 and 4
 
        
             
        
        
        
Step-by-step explanation:

 
        
             
        
        
        
Answer:
A, B, D, F
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
The dolphin will be above the surface of the water for 2 seconds.
Step-by-step explanation:
Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
 .
.
This polynomial has roots  such that
 such that  , given by the following formulas:
, given by the following formulas:



The height of the dolphin after t seconds is given by:

According to Micha's model, how long will the dolphin be above the surface of the water?
It stays above the surface of the water between the first and the second root. Initially, it is below water, when the first time for which  it crosses the surface upwards, and then the second time for which
 it crosses the surface upwards, and then the second time for which  it crosses the surface downwards.
 it crosses the surface downwards.
We have to find these roots. So


Multiplying by -16




4 - 2 = 2
The dolphin will be above the surface of the water for 2 seconds.