Answer:
6 seconds
Step-by-step explanation:
<u><em>The question in English is</em></u>
An object is thrown from a platform.
Its height (in meters), x seconds after launch, is modeled by:
h(x)=-5x^2+20x+60
How many seconds after the launch does the object reach the ground?
Let
x ----> the time in seconds
h(x) ---> the height of the object
we have

we know that
When the object hit the ground the height is equal to zero
so
For h(x)=0
we have

The formula to solve a quadratic equation of the form 
 
 
is equal to
 
in this problem we have

so
 
substitute in the formula
 
 
 
 
 
The solution is x=6 sec
The he object reach the ground at x=6 seconds
 
        
             
        
        
        
Answer:
See Attached
Step-by-step explanation:
See Attached for proof of RHS = LHS
 
        
             
        
        
        
Answer:
He bought 3.3 cents
Step-by-step explanation:
I hope I am right
 
        
             
        
        
        
This is an example hope this helps
 
        
        
        
Answer:
198 degrees
Step-by-step explanation:
Such a shape is called a 20-gon, such shapes have an interior angle of 162. Hence, the exterior angle = 360 (Complete angle) - 162 (The interior anlge) = 198 degrees, Hope my answer helps you, Thank you, and please add me as brainliest! Thanks