Answer:
see the explanation
Step-by-step explanation:
we have the quadratic equation

This is a vertical parabola open downward
The vertex is a maximum
Find the x-intercepts of the quadratic equation
The x-intercepts are the values of x when the value of y is equal to zero
so
For y=0

Solve the quadratic equation
The formula to solve a quadratic equation of the form
is equal to

in this problem we have
so

substitute in the formula





therefore
This parabola has two x-intercepts representing the times when the dolphin's height above water is zero feet
I'm not too sure myself (cause Im a learning student myself at the age of 16 and I learn it in a completely different language) I cant really understand c) sorry for my poor english but I think I have gave you enough tips to do c)
it would be c 9/25 and 9/25
No it is impossible because 9x7=63
The dimensions of the bottom of the drawer are:
20 cm × 40 cm
So the area is : 800 cm² (rectangular shaped)
The area formula of a circle is:

r²
The diameter of the plate is 20cm
so the radius is half the diameter which is 10cm
Apply the given to the formula:

(10)²
100

314.16 cm²
2 plates in the bottom drawer
Area of two plates:
2 × 314.16
628.32 cm²
Area of the non-covered space in the bottom drawer:
Area of drawer - area of two plates
800 - 628.32
171.68 cm²